Firstly, the review by RGB is top class and should be cross referenced in the TX30/35 reviews as comprehensive comparison of models.

I've had my OT15 for over a year and can't speak highly enough of it. We have a smallish (7.5m x 3.5) kidney pebblecrete pool. We get a moderate amount of leaves but I just let them sit there and put the robot in every two weeks which probably helps with the life of the unit. I'm amazed but it picks up mostly everything in one cycle, sometimes I put it on for two if there are a lot of leaves. It sometimes misses ...Read more

Here is the bottom line: with a few adjustments to your technique, this robot is reasonably effective as a pool cleaner (3*). It is seemingly without peer below $900 (5*). So overall it earns 4*. Now for the detail. First, note that the Zodiac TX30 (TX 35 without trolley) is with three exceptions identical to the Zodiac OT15 and FX18 cleaners. The exceptions are:
(i) price: the TX30 is intended to be sold through full-service pool shops, so it is much more expensive than the OT15 and FX18 which are intended for on-line stores and available on ...Read more