I'm assuming you mean the adapter to use PS2 peripherals on the PS3, in that case they are all 3rd party and it's really just a flip of the coin as to which you wish to purchase. As for lag issues I don't know.
I have this pelican PS2 to PS3 converter and it works perfectly. I use it with my Tekken Arcade Stick for PS2 to play Street Fighter 3: 3rd Strike all of the time and there is zero lag.
Ok, just checking. I've heard rumors of some being better then others. People say the pelican one is good. Others say the guitar hero tac is good. The reason why I'm asking is cause I just ordered a HRAP2 and want to get the best connection possible on my ps3. I have these other ones I ordered on ebay that cost me like 5 bucks each one, but don't know if I'm getting the best output.
Markman on SDTekken/Tekkenzaibatsu/SRK tested out the Inpin PS2 to PS3 converter and that one is the best substitute to the Pelican converter. You have to PM Laugh on SRK to get one or two imported.