I'm a Disc/ Holy Priest and I find using Grid with mouseover macros to be the most efficient. Vuhdo and Healbot are nice, but they tend (at least for me) to be glitchy and not as responsive as my Grid/ Mouseover macro set up.
I've done a couple of video tutorials on how to set that up if you wanna take a look:
Keybinds are on your account and/or character specific, not computer specific.
There's no 'best' addon--there are hundreds of threads about grid/clique vs healbot vs vuhdo on every forum even slightly related to wow ever.
Try them all. Healbot is easiest out of the box. Grid is hands-down the most obnoxious to install. I recently switched from HB to Vuhdo because I wanted the 'cluster' feature for CH grouping being visually shown to me. I like that, unlike Grid, VuhDo will show you the icons of buffs/debuffs instead of little colored dots that you have to remember.
I recently healed through first quarter of ICC on my holy paladin. I use vuhdo as a healing addon. Although you will have to adjust many things on it. Some stuff like Smart Cleanse and Auto trinket use are alittle annoying in certain situations. Grid + clique is a very nice setup too. When i used it before i couldn't set just a normal right and left click as a spell though which you can do with vuhdo. I agree with a few posts up though, vuhdo bugs quite a bit. If you use main assist and those sort of settings in your raids then it will bug out.
er- which is best for clickers/keyboard turners that arent yet used to keybinds? and is there any way to disable keybinds
Any click-healing mod will work fine. Personally, I click for almost all healing and save my keybinds for DPSing and certain buffs like hero and dropping totems. I still habitually keyboard turn a lot, but that's because when click healing, mouse movement really isn't the best plan.
Like most have said it comes down to a personal preference. What works best for you but before you can figure that out you gotta know what all you want to be able to do each of the addon has great features and can do alot of things but some are better doing certain things while others just make the basics simple. I like healbot its easy to use out of the box and can be setup to do anything you really want to do if you dont mind a lot of button combo's. the response time on it is good for me and i can easily get the job done. I also have grid installed to help if i need it but rarely use it.