Original Infinity is 2A limit, and you have to put the batteries in in the right order (no reverse battery protection for the PV), but it's just a really nicely working PV. Definitely no button issue with it, it was my daily for 6 months before getting the BP.
I'll be tossing in an IPro delrin cap, slightly munged threading (turns out you need to grind the threads slightly to put IPro cap on original Infinity), but it actually does work fine, provides the added pop-off safety feature. (I didn't buy the cap for pop-off, I just wanted it for its off function, when I put it in a pocket.)
Good luck!