[GadgetKen]

Originally was sent the MaxRoam Israeli card with a "Yackie" discount for switching. Didn't work properly so they sent a Belgian replacement. It does work for send/receive text messaging and for outgoing calls (haven't tried incoming yet). Call placed on T-Mobile did not work with standard direct dial with + or 001 code, but did work with alternate *182*001*******# command on T-Mobile USA to dial my office voicemail. Callback was fairly quick, had very good voice quality, and I was charged 1.01 Euros for a short USA to USA call under a minute. Error message or incomplete calls were charged half a Euro each. Cumbersome dialing method but I can program a few common numbers into the sim phonebook.
Reason for switching sims was given on their zendesk csr system as "We have had a failure of our SIM toolkit on a select batch of SIMs, this is the software on the SIM card that allows you to make cheap and receive cheap roaming calls. Unfortunately your SIM was part of this batch and we will ship you a new SIM, free of charge. If you could please email us with your current address we will see that a new SIM is shipped out to you immediately" rather than a problem with the underlying Israeli carrier.
Most recent zendesk csr response gives some hints on dialing and switching carrier that I found helpful:
"I'm afraid that due to upgrades to our system some parts of the website are unavailable. Unfortunately this includes the reactivation page. The sim card was preactivated though so you can use it to make and receive calls and sms messages. You can also top up by using the following link: https://www.maxroam.com/MyMAXroam/TopUpExternal.asp
I'm afraid that these upgrades are essential as there are some changes to our service. For example, you now have one number for voice and text. On the reverse of your card you will see a number beginning 048. If you put a +32 and remove the 0 from this number you will have +32489XXXXXX. This is your new sms number which you can also take calls on.
We have dropped our priced in 55 countries by 50%. We now cover 26 new countries and your sim is now data enabled.
We aim to have the website running as normal as normal as soon as possible. We apologise for any inconvenience caused in the meantime.
With regard to your issue making calls, Please check your credit balance first of all. If you have enough credit to make a call, then please turn your phone off for 90 seconds. Turn it back on and allow it another 90 seconds to start up fully. Then try to make a call using the *182*phonenumber# format. If this still does not work, please try select an alternative network and place a call. If none of this works, please contact us again."
Bottom line is that the new sim is functional but they really need to do more work to get everything working properly. We'll see whether they can pull this off...