I have both the PigCig and the Elegant. I have never had a problem using 808 cartos from any other vendor (V4L, Cigeasy, Nhaler, to name a few) with the PigCig. However, it is true that the 808 cartos I have from LeCig (for the PigCig) do not work on the Elegant or any of my V4L batteries because the LeCig cartos don't have air slots in them.
I have a major problem with the PigCig and that is that what starts out as a beautiful chrome finish (just the band, on mine, since the rest is black) becomes a tarnished and UGLY blackish-steel color after just a few days of use. I called the vendor about it. I was told that they know about the problem and it affects the silver and gold colors as well as the silver band on black (sheesh! glad mine's only the band, not the whole thing), that there's no known polish they're aware of that will restore the color and that they're working with their vendor to see if they can put "a coating" or something on them to prevent it (in the future). No offer to resolve my problem of any sort. I responded by ordering an Elegant - which is beautiful! It's a little smaller (shorter) than the PigCig, very good looking (with no tarnishing issues) and it actually lasts longer between battery charges (750 mah vs. 650 for the PigCig). Plus, it was cheaper. No brainer for me - I definitely prefer the Elegant.
And the others are right - the GoGo has it's own cartos that aren't compatible with any other brand right now, though I hear 510 adapters for it may be in the works. Haven't heard anything about 808 adapters.