i love my smart tray. its nice cause you can take care of different types of batterys with it. everything from old 2400 nicd's to the new 38's or even the 42's all you have to do is change the setting or choose deadshort mode.
the only downfall i see with the tekin battery doctor is that to truely see all the benefits of it, you need to buy one for every pack your plan on running for raceday. from what ive been told by people using them, thier batteries perform best when left on the tray for long periods of time. not just a quick voltage pulldown. so youd have to tray them 1-2 days before you race, and charge them right after pulling them off to see the largest benefit. but in that respect id like to see a comparison against a battery that was smart trayed. to see whether holding it at .5 volts gives a battery better performance than one thats just been equalized.
Mine: Nomadio Sensor; T2'007, Keyence, Express; ZX-5 SP, Mamba Max; XB8, OS V-spec and NR P5; ProBoat Shockwave 36
My Son: Futaba 3PM; T4 RS; Clodbuster; TT-01;Zig-Zag racer