I've got both, Losi RTR (bought as a roller from dollarhobbyz for $375) and RC8.2e FT.
Ended with upgrading 8ight to a kit, it costs a lot but it's worth it.
Differences - kit vs rtr - are:
- hinge pin braces
- chassis (RTR is heavier and kit is 7075)
- shock towers
- shock caps

RC8.2e is an obsolete design, it's a good buggy for beigneers but need a lot of tuning parts if you want to race it with sucess. I converted it with Tekno v4, added some option parts and it's much better car now. Still, Losi beats it in every way on the track.
So my pick would be Losi.