Looked at the top three companies for this technology. COIN, Swyp and plastc.
I like the idea of the universal card, I have 5 cards.
Swyp won my vote, I have ordered two, main reason for going with SWYP was expand-ability and rechargeable 2 year battery. Not to mention 25 cards support and lowest price of them all.

Use this link to order and save $5

http://www.swypcard.com?ct-referral-code=YlCeUlz1