You have alot of good feedback but I'll throw my opinion in there two. I actually own both, I got the RSST first and was only about to make it 2 weeks before I hated the thing. I bought the kayfun and havent touched my RSST since. The flavor, vapor production, build quality, reliability, and everything else is soooo much better on the kayfun. You definitely will not regret buying it. Also it is much easier to build. I had a hard time with hot spots on the RSST