4 gears vs 5 (though i did find a TS once with a 5 speed box)
Plus the TS only has single transfer ports. It just doent tune very well, when i started 7 years ago someone was trying again with a TS (Steve Cannon?), but it was very slow.
I reckon a ETZ with yokes like Chris Rogers has to be the best bet, the trail is all wrong so they are mega unstable on the brakes, Chris's yokes must help sort that and you get the best of both worlds. I rode both a 251 frame and a ETZ and managed a 57 round brands indy on both, but my time on the ETZ was faster and it was much easier to ride. The 251 frame was way better on the brakes than my ETZ because of the trail issue.