A quote from a US user of the FreedomPop global hotspot:

"Speedtest.net identifies the location of the sim as being in London. Looks like they are running the sim off of the Three UK cell network."

Looks like FreedomPop is piggybacking on Three's data plan.

It's definitely been confirmed on other websites that the FreedomPop global sim is using Three UK. Despite being in a LTE hotspot (basically an unlocked version of an AT&T/Novatel Mifi Liberate) the signal is reported as only 3g. It can function in 3g on either T-Mo or AT&T in the US but is reported as having high ping rates of around 200-300 ms due to running off UK servers.
Tempting because it would give me access to data networks other than my current access to Sprint (FreeedomPop CDMA or Karma) or Verizon (through wireless tether). But I'm hesitant to sign up for the freedompop global offer due to:
-Lack of coverage other than US and Western Europe. I'd like to also see Canada, Bermuda and Non-US Caribbean coverage.
-Reported long ping times on internet connections in the US.
-Problems with availability of sim cards. They recently restocked but were sold out again within hours. I have a decommisioned hotspot similar to what they have in stock, so wouldn't want to pay for a second one.
-Slick business practices by FreedomPop. When signing up for FreedomPop Sprint CDMA coverage, I had to deselect the 30 day free trial of paid service, additional unwanted service add-ons that would be auto-billed quarterly, and automatic top-ups(they now charge a US$5 fee for that where I paid nothing at the time). Then I added FreedomFriends (for 50 mb/month per added friend up to a max of 500 mb extra a month) and I also shift unused data between my three FreedomPop CDMA devices to boost my usable data allotment. While I understand FreedomPop has to make money to stay in business, you have to jump through hoops to get the optional truly free service from them.
-Varying degrees of customer service on the odd occasion I've needed it. Sometimes good and sometimes not.
-No voice or SMS access on FreedomPop Global sim cards other than through VOIP or SIP based services.

I agree it has some catches, but getting 600 or 700 MB of data per month (by using the Freedom Friends program) for free (assuming you know how to disable their "catches") is still a good deal. 300ms pings aren't that bad, nor are the reported download speeds (4.0 to 5.0 Mbps down, 1.0 to 2.5 Mbps up). Plus the fact that said data is usable in the US and Europe.

Really, as long as you're someone who can read instructions and take precautions (i.e. use a virtual credit card with a low limit), this is a no-brainer if (when) it's available.

Might sign up for FreedomPop Global once they have coverage in the areas I need it in. But no data coverage in Canada, non-US Caribbean and Bermuda make it of limited use to me. For US, I have unlimited Verizon (in theory; I can't use it that heavily or it would likely be throttled or cut off), plus ~3 gb free a month on FreedomPop CDMA Sprint, and a lot of non-expiring data on Karma CDMA Sprint with the ability to earn more free.

Will be in Bermuda for a couple of weeks starting at the end of May, and will be using limited free hotel wifi, Kindle free 3g and InMarSat voice for my data and voice needs. Used to have a Digicel Bermuda sim but they increased the minimum monthly refill and started charging daily license fees on pay-as-you-go plans (other than the flat rate prepaid plan that still charges for international calls to US and elsewhere). Also used to have Telna but they tripled Bermuda rates. Might pick up a Piranha sim card as a backup.

I can recommend Piranha if you travel internationally. While they won't match a local prepaid SIM, their rates are generally reasonable in pretty much every country, i.e. $.14/MB in Bermuda, which would allow you to check email and news without breaking the bank. That plus a 420-day expiry make it a good backup SIM if nothing else.

Since Piranha transactions are in British Pounds, now is a good time to buy, as the Pound hasn't been so weak against the dollar in over 10 years.

I've asked them more than once about selling the SIM on its own, as I already have some mifi routers, and I don't think the spec of theirs is ideal for Europe. They keep replying telling me the frequency bands in the spec, and I keep replying also telling them the frequency bands, i.e. no 4g and no 900 MHz 3g.

The FreedomPop Global mifi device is a Novatel 5792 (aka the MiFi 2 or the AT&T Mifi Liberate in the US). I have the AT&T version but discontinued postpaid service on it when I found less expensive prepaid alternatives. It's a decent mifi device but on rare occasion I have had to do a battery pull when it got glitchy.

Agree FreedomPop should heavily stock up on the GSM/3G sim cards and not just try to push the mifi device and sim kits(how tough can it be to buy a few thousand private labeled sim cards?). Many people already have USB sticks, mifi devices and wifi hotspot enabled handsets and don't need another router...

I like my CDMA/LTE FreedomPop USB and mifi devices on Sprint service in the US, but will wait on trying the new FreedomPop Global offering until they have more coverage where I need it and stand-alone sim cards are readily available.

I went ahead and ordered the Piranha Mobile sim card on the GBP50 option (basically the sim card is free if ordered with the large reload). Plus used a credit card that has no international transaction fees. Unlike FreedomPop Global, I know Piranha will work in Bermuda on an upcoming trip, and I can also use it in other countries that FreedomPop does not currently serve. Probably will swap the sim card in my CAT B100 rugged phone so it will work fine hiking or at the beach. It will be a good backup to my prepaid InMarSat phone if there's an obstructed view to InMarSat-4 Americas or it's pouring outside.

Andy, if you're in the UK, wouldn't it make more sense to use one of Three UK's SIMs which is basically the same thing (free 200MB data usable in Europe and the US)?

If you really want a US FreedomPop SIM, they went on sale last week for $.99 with free shipping, but sold out in a few hours. I'm guessing they're using a first run as a beta test of sorts, and that more SIMs will be available soon.

I will be getting one of those Three SIMs soon, but its free roaming is in a different list of countries, 10 European and 8 others.

When FreedomPop Global restocks sim cards, I may get one of those too. But I'm in no rush since it's really a data only sim card and it doesn't have coverage in several countries I need it in. The current FreedomPop Global mifi device would just be a paperweight in Bermuda, where I know Piranha and InMarSat will work just fine there. I like FreedomPop CDMA Sprint in the US for the complimentary gigabyte I get on each of my FreedomPop devices, but their FreedomPop Global GSM offering looks like it still is a "work in progress".

I just got an email from Piranha that my order is marked as shipped and they also included a complimentary second sim and to take both sims when traveling (I ordered one with GBP50 on it and they also are including a spare with GBP5 on it). Unlike FreedomPop Global, Piranha appears to have no shortage of sim cards :) The phone numbers on both sim cards (one is Jersey City, NJ and the other is El Dorado Springs, MO) are registered as "Mobile-Telecom North America Mobile" when I checked the numbers on WhitePages.com. I used to have a Telna postpaid sim card but cancelled it when their rates changed shortly before their being acquired by G3 Telecom of Canada. I'm guessing Piranha has some sort of agreement with Telna/G3; Piranha rates are very good for voice in the countries I need it in. For instance Bermuda is less per minute for outgoing international calls back to the US than what I would pay for a local prepaid sim card on Digicel or CellOne (local carriers charge a flat BM75 cents/minute for international long distance where Piranha is USD42 cents/minute).