I run the ECS STS and I'm fine with it, I like the ability to change the length of the shift throw and the weight or feel of the shift, however the ECS shifter gets more mechanical or "notchy" as you shorten the throw. When using a STS mechanism like the ECS or an oem Audi unit there are other modifications that need to be done that I feel are also necessary to really get the full benefit of a short throw shifter. Like replacing the rubber parts in the linkage bushings and bracket bushings, and the side to side lever needs some toying with, 42 draft designs takes care of the linkage bushings and s2s lever.
The sigma six and twm STS units replace everything, with the exception of the bracket bushings which can be purchased from tyrolsport. These STS mechanisms are top notch, the sigma being the superior option, the only downfall to these units is they can be problematic to dial in.
Either way, if done correctly, you will have a good STS that is drastically improved over stock.