I have yet to see an aftermarket TC setup that I've been impressed with (Including Bazzaz). It is pretty old tech and like Gawernator said, there's a point where it's more detrimental than helpful. That being said, I still believe the factory integrated stuff is a better than the aftermarket stuff. Like anything else, this is largely subjective as everyone has different needs. I would argue there are 2 categories of riders:
1) Those that like the technology to assist them in going as fast as possible (Gawernator and I are in this)
2) Those that just enjoy riding (street/track days) and any kind of additional safety net that would help prevent a crash.
At the end of the day, people in the first category will sacrifice that safety net 99.9% of the time if we find it being too intrusive. The more crude systems can also harshly cut or alter the power delivery - so you go out and race, have pretty good lean angle, then the TC kicks in and upsets the chassis and completely messes up your corner exit drive.
I wouldn't say what's out there is bad, there is just a lot of room left for refinement. What makes the systems like the R1 work so damn good is that it takes in all the data on the bike - throttle position, lean angle, front wheel speed, rear wheel speed, RPM, etc to figure out exactly how much/little intervention to give, where as the Bazzaz just has that little dial (1-8 or something like that) and goes off just RPM or a rear wheel speed/RPM combo
Years ago I did a lot of reading on the Bazzaz system and I concluded their TC is garbage. I don't recall all the details of how it works but it seemed pretty primitive, something about change in RPM, nothing with wheel sensors.
The Nemesis TC system I had on my Ducati was top notch though. There was a reason it retailed for $2500 not $600-700 or whatever the Bazzaz was. It had sensors on the wheels it worked by measuring the change in the rear wheel speed relative to the front, while also taking the lean angle into consideration, that way you could still do a wheelie, but when you were at full lean it would kick in when you got on the gas really hard. It had 8 settings, but realistically for a racer settings 1 or 2 were about all that was needed. In the rain maybe you'd want to go up to like 4-5, but I never tried that. Of course that system was developed at least 10 years ago. At the time it was the best system available for people to buy, and there weren't any OEM systems except for the ones used in MotoGP and WSBK, not available to the rest of us. Nowadays, all the modern liter bikes come with better and more refined systems.
I do remember one track day where I forgot to check my belly pan and it was full of water from the night before, and the first session in the morning, the first turn I hit (fast one, about 80 mph turn), the water poured all over the rear tire and it went sideways on me. TC light up like a christmas tree and I'm 100% confident that if it wasn't for it, I would've highsided to the moon! lol Kept me in check though, just a butt-pucker moment.