I've had the Smokenator for about 1 1/2 years now and have had good success with it. On my first cook, the steel warped because of the heat exposure (followed manual exactly). The smokenator is now slightly twisted and I have to make sure the fit is good with the bottom grate before adding anything hot to the mix. The water container also requires hourly refills, making temp adjustment an hourly concern.
I just got the Slow N Sear (arrived today) and the quality straight out of the box is impressive. The reason for the purchase was extended cook times. This item, just like the smokenator, is made out of stainless steel. The difference, when you pick up the Slow N Sear, you know you have something special. The smokenator is light weight, but when you pick up the Slow N Sear, the quality of build is evident. The open top design can only improve the searing capability (tough to do on smokenator). I can't knock the Smokenator but the Slow N Sear has serious potential. Will update with user experience.
I learned about the Slow N Sear on Amazing Ribs and after having used the site for a couple years, I trust the recommendations.