It definitely depends on what courses you've already taken, how long ago you took them...
I studied intensely for two months before the April exam (about 4 hours a weekday, and fully length exams every other Saturday/Sunday). You'll have to determine how much you need to review/re-learn/recall. Don't spend too much time memorizing formulas and facts, though. Jump in and start taking practice passages (timed) as soon as you can. You'll get used the to the type of questions they ask.
If you need the discipline, then take a course. I'd recommend Princeton. Or you can just get a set of their material without taking the course. I found the lectures to be a repeat of the course books. It was a time-saver to just read it for myself and do passages on my own.
Berkeley Review goes into too much detail in my opinion. Also, their Verbal section is not representative of what's on the MCAT. Use Princeton's Verbal material + practice exams. I don't know about Kaplan. Hope this helps. Good luck!