The only bot you should really trust is the bot you make yourself, regardless of the platform you base it on. Yes, there's lots of honest people who release scripts to the public and some of those scripts are room bots for either games or protection, but it is like anything, there's a fair few rogues out there too and the only real way to find out is to download and install which IS the big risk.
Whilst I release a general purpose script I have chosen not to release a bot. This is because people are more discerning about them and want them to work in a specific way at times. Often this isn't a practical way to deal with it because the more features and configurability you place in a bot the slower it will react to its tasks. This comparison is usually only milliseconds but it also depends on how important a bot's role is. mIRC is quite satisfactory as a bot unless the bots role is going to be quite intense. I currently use one for a few reasons, one being security and the other, general room management in about 6 rooms. It does the job. If you want something with industrial strength you'd want to make a dedicated one.
Remember also that bots need to be hosted somewhere. If you have an always-on connection then your problem is solved as mIRC, Eggdrop (Windows version, often called a Winegg or Windrop), or a custom made one will run fine on Windows. If not then learning Unix and paying for a shell account is the only real alternative.
