With LazyRaider you have configuration options, with CombatBot you do not. LR allows you to use/not use plugins, allows you to enable/disable framelock, allows you to set your TPS, allows you to select a tank, allows you to follow a tank (and specify a range to follow the tank), allows you to set whether or not you have a tank, and also allows you to set a pause key such as LSHIFT, RSHIT, LCTRL, RCTRL, LALT, and RALT. There are other options that I may be forgetting, so I suggest getting the latest version to check it out. CB has no options. It's just a bot base you have to enable and disable by stopping and starting the bot. That is, however, if they haven't updated CB to a newer version than what I last used.
My personal preference is LR. I like options.