I myself have a 26650 Simplicity on order and if it's even 80% of the other Super T products I own, it's going to be awesome.
The other ones I have are clones. Tobeco Hades = garbage, utter garbage. Tobeco Mutant = very, very nice. Infinite brass Stingray = very nice, once I sanded the button and tube to stop the sticking. Angelcigs Kingpin = just slightly less garbage than the Hades.
For toppers, I have a copper Tobeco Tobh, which works just fine. It's always been mounted on my Mutant and I really like the combo. The authentic Cerberus would probably be great if I could ever get the taste of machine oil from it. I originally bought it to hybrid my Hades, but I hate that thing. The last is a 26650 Kayfun from Tobeco. Works great, no problems, other than it is freaking huge. 26650 RDAs have pretty good juice capacity, so unless you need, and I really mean NEED, the capacity, I would pass on a 26650 tank. I've considered getting the Mutation XL, but I've been able to convince myself I really don't need a 26650-specific topper.