Well the thing is, with the Pelican USB converter it was designed for use with GH1/2 so lag was a HUGE issue. The guy that helped design it was also a big fighting game fan, so you can kinda see why the Pelican converter ended up being as good as it did.
The REAL one will be made again after the Olympics (supposedly), so hang tight.
The TAC one does have lag, but honestly it is hard to tell if someone can 'feel' lag and input delays. I know I am VERY attune to it because it is something I test/look out for ALL the time now. So if there is very little/slight lag I will notice it and yes it will annoy me. It doesn't bother most people out there, but myself (and many fighting gamers/competitive gamers) will bring it up as a major flaw/issue.
I hope you found the review for the TAC helpful. For the most part it works. If you're playing fighting games on your PS3 it should be fine (T5DR, Battle Fantasia, VF5, SC IV, etc...)... If you're using backwards compatibility for PS1/PS2 games on your PS3 however, the lag might be a lot more obvious. There is mandatory 3 frame buffer lag for the video signal on the PS3 (ALL MODELS) when in BC mode. So it'll be 3 frames of lag + the slight 1-3 frames of lag on the TAC converter.
4-6 frames of lag might not seem like a lot. But in the fighting games I play, 4-6 frames is a big difference. Now before someone mentions stuff about the human eye/reacting to 4-6 frames is impossible, etc... It's not SEEING it... it is feeling it. If you can already do things that require frame specific timing and then immediately try it using something that lags, you WILL KNOW.
Sorry for the semi long post, I hope my explanations are helpful to you!