Out of all the current advanced timing speed controllers I believe they all perform pretty close to each other. They all have plus's and minus's to them. Nothing is ever perfect. Realize what weakness you see in the speed controller your using first, then work around it. Then utilize what strengths you see and use it to your advantage. In the end my opinion is that the majority of the performance you get out of whatever brand of speed controller you use, depends on how well you have it setup. How well someone knows how to set up gearing for their speedo, what profile for a certain track, etc will make them the person to catch on the straight away and the infield.
I personally like the Tekin. And I haven't been outrun by anyone while using it. When a Tekin hits turbo it LAUNCHES. At top speed the car sounds demonic I love it
Another thing I like about it is that I can gear my cars short so I can have insane low end, and because of the turbo function, have the top speed if not more, than gearing my cars tall. I also like getting free updates and having a lot of control on tuning the speedos settings to my liking. What I don't like at the moment is that it does have some brake issues. If you don't let the car get into turbo timing the brakes are very strong. If your in turbo for a long time, the brakes are still good but noticeably weaker. Its not a big deal to me anymore because I have worked around it. I just set my car up to not have to use brakes much
I used a SPX for awhile beforehand, and it is a nice speedo as well. Pulls nice and smooth all the way up to top speed. Very fast and easy to make changes at the track, so I think a little quicker to use in figuring out gearing for the day. It may just be in my head, but from what I remembered, it seemed even if you were off on your gearing some it could still pull pretty hard out of the corners. Top speed is very good, doesn't really feel like it's going to top out, keeps on pulling. Also the brakes are intense. You can literally flat spot your tires by slamming the brakes. What I didn't like about the SPX is that I blew my first one up. The second one I got was fine though. I also wished I had some more adjustability on the advanced timing profiles.