Just got my 3.7/+6V Prodigy in today, and didn't quite know where to post this, but I guess here's a good spot (the most relevant anyway). Performance using 3.7V 2400mah ultrafires is exceptional. I don't have a 5V PD to compare it to, but comparing it to my DIY PT @ 5.2V its pretty close. Vapor is a little "cooler", but still better than a regular battery. Plus, with 2400mah, this thing should last quite awhile before needing a charge. Going back and forth with an M201 (via DIY adapter [Steve... you want to make a M201 adapter (waves hands in a Jedi-like manner)]...did it work?), 801, and 901 I'd say the best performance is with a penstyle. Vapor and flavor is MUCH more pronounced with the pens than with the 901. I give credit to those satisfied with 3.7V on a 901... to me it needs more voltage than that. I have a 510 adapter as well as a 5V switch assembly on the way, so if nobody posts on these, I'll give an update/comparison when they come.