I like the idea of text-link-ads, but the 50% commission is too much. Its a fairly simple system that I can see someone copying for a much lower commission. I wont run them with that high of a commission.
I work with TLA for two years and like them in spite of their commision. But the comission is a bit high anyway.
Their affiliate program is good earner for many bloggers. John Chow made nice amount from TLA affiliate program.
Well I wouldn't touch them now because of the whole paid links thing going on with G at the moment..... DoA