[GadgetKen]

Have been using an MFU V200 dual sim quad band phone I picked up on ebay from a Hong Kong dealer for US$53 including registered airmail. Decent audio quality. It's a sturdy, if somewhat basic, phone. It's a dual active sim and a bluetooth headset can run off either sim card.
In US, I use an AT&T/Jolt prepaid and a T-Mobile/Tuyo prepaid sim card in it.
When I go to Nevis at the end of February probably will use my Digicel Bermuda card, and will likely use up the last of my airtime on my MaxRoam card as the second sim (probably in St. Marteen en route to Nevis).
It's nice having two active cards in case I'm nearer to a network tower for one carrier than another, or the rate is cheaper on one sim card than another. Also can access the directories on either sim card to dial a number.
One glitch I've found is if the second sim card defaults to the same carrier as the first sim, and a call is rejected on the second sim (no roaming agreement other than emergency calls), then the first sim will not be able to make calls until the phone is turned off and back on again. Happens when I use the T-Mo/Tuyo card in rural areas only covered by AT&T. Easiest way to avoid this is just to not dial with the sim that says "emergency only" instead of a network carrier name.