I've been using the L2 atomizers and batteries for over a month and they have worked perfectly so far. I've actually been using the L2 510s at 6v and they perform much better than a standard Joye 510 in my opinion.
Only 1 of the L2 510s I received with the starter kit has died, but I really did torture the bugger and sometimes was putting 8v through it (yeah be careful with new LIPO4 batts

).
The carts from a Joye 510 kit are a bit lose on the L2 attys but not so much that I mind (then again I usually drip in 510s). The performance of a filled cart with the L2 510 seems to provide much more flavor than a standard 510 with just a small drop in vapor and throat hit.
I've also been using the L2 parts with all kinds of 510 products from other companies. Everything is perfectly interchangeable except for the issue with the lose carts.
Besides cartos, I think L2 510s are the only other atomizer I'll be using on a HV device. For now anyway...