For quality and compatibility, I'd say get a good brand of discs that work well with your writer and forget about booktypes etc. I've never had a player that refused -R and only played +R. Of course, I use verbatim media, which is considered the best media around.
There's probably a load of idiots out there that did tests and found +R to be more compatible, but if you are comparing a load of -R and a load of +R media all of different manufacturers, you'd find that -R is a bit more common in stores and the quality can be worse since there are more of them.
I'd only ever trust a test that included ONLY one type of media for their + and - comparison. Verbatim for example. If they compared MCC03RG20 and MCC004 in 150 different dvd players and found MCC004 to be more compatible, then I might believe the result. Only of course if they also tested all burnt discs on professional quality scanning equipment as well just to make sure the results weren't caused by bad burns instead of the + or - format.
So basically what I'm trying to say is that a really well burnt disc should work fine regardless of format/booktype. Unless it's Dual layer media. That's a whole other story.