I recently started using it (2 weeks ago). Once you get passed the initial confusion of setting it up (The guides sometimes assume you know what "this" or "that" is), then it usually works very well. I've been using one of the more complicated parts (questing bot) and I've done 2 1-85's already. As for farming, it's damn near flawless from what I've seen. There are many many routes on the forums, plus a plugin called ZapRecorder that makes it easy to make your own, and you can even import some routes from other bots.
As for being noticed... I really think that depends on your settings and what plugins you have or don't have... My bot got stuck going in circles for about 8 hours, but no one noticed ;P. Sometimes it does do stupid things. I'd say get a profile set up, and WATCH it for a good while to make sure it's not doing retarded things, and you should be good.