tell us what you want to achieve and maybe we can pick a bot that will fit that need.
each bot is a little different [otherwise there would only be one] so each bot fills a need a little differently.
i use combat bot when i need to finish a quest by hand. i can stop questbot flip to combat bot and no other changes and my char will still fight, but i have to move the char manually. but combatbot is simple and not great for everything
i used raidbot for a bit, but it didnt really fit my needs.
the next one is lazyraider. you can use your combat routine plus lazy raider plus a plugin called iwantmovement for an auto raider format. much like using dungeonbuddy to complete raids. each one has different abilities and settings.
then you get into non-movement combos, i think the most used is Tyreal+PureRotation for a player controlled movement bot. this combo is nice for high movement required fights.
so...tell us what you want to do with HB and we can help
Pretty much sums it all up, with a few minor extra differences:
1: Raidbot is Combat Bot with Framelock enabled by default. This IS a DPS or healing increase, but there are combat routines who do not handle this well (Like TuanHa's routines), PureRotation, Demonic, Leaves and Fury Unleashed handle this very well.
2: LazyRaider is a nice product and one of a kind. It supports alot more like movement, following tanks etc. But this does come at a cost of performance. Even with framelock enabled, RaidBot and Tyrael perform better. Keep in mind that this combatbot-replacing bot has the most options!
3: Tyrael is basically RaidBot AND Combat Bot, but with extra options. You can enable or disable the Framelock function (Improved DPS/HPS when enabled), you can set the amount of ticks you wan't the routine to run with (Raidbot is by default 30, Tyrael you can set whatever you want up to 200). And you can set your Pause keys, while RaidBot does not have this option. And you can enable or disable plugins, which are disabled in RaidBot.
Tyrael is RaidBot on steroids

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All 4 are good. For absolute speed during raiding, I'd suggest Tyrael. Otherwise all are fine.