I have SM-1 and like it a lot. I also have a CCM T2, my son has a Kaos Pump as well.
My T2 is stock with a 10" Deadlywind Fibur Barrel.
The Kaos has a new feed neck, on/off and a 12" CP .685 barrel.
The SM-1 is stock with a CP regulator and rail mounted on/off & plain rubber grips. It has a 12" Deadlywind Fibur Barrel.
While the T2 is the best of the group, the SM-1 holds it own and is far more comparable to the T2 than the Kaos Pump...by a lot!
I almost purchased an Empire Sniper; it is not nearly as trick as the SM-1, though I think it is quite a bargain and the best bargain for a new gun for someone starting to pump and is on a budget.
The Kaos is the worst bargain in this group, after you get done upgrading the barrel, ASA and feed neck you are into it for $300.00, and it still is inferior to the rest of this group.
Now this only addresses NEW markers and there are a lot of other good choices for those that like to tinker.