from my pov:
1. tower - useless/sloppy/broken in game gui, works only on not protected servers out of the box, on the other hand it has most advanced scripting api with full packet support, don't really like lua tho.
2. zranger - the only pvp oriented bot, with decent in-game widget system, decent scripting api with own useless and limited syntax but at least with good packet support, doesn't work on most servers out of the box.
3. adrenalin - almost perfect out of game gui, bypassing number of antibots after updates, nice scripting language, but sadly poor scripting api with many basic functions missing, lack/broken packets support, poorly maintained and slowly developed, retarded pricing policy.
good bot could still milk a lot of $$ out of melting community since ppl are willing to pay for botting,
that would be adrenalin with cons fixed and in-game radar/widgets added to offer pvp content (since for pve it does more then good).