I'm sure this topic has been asked to death, but I'm new to the forum and could use some help.

I'm planning on taking the GMAT towards the end of August.

I studied for about 3 months last June-October, but took an new job and never took the test. (if you miss your exam, you don't get penalized or anything just lose your money, right?)

I'm studying now and will use Kaplan, then move to Manhattan GMAT books (I notice there are 2 MGMAT companies, blue covered books and red colored, which one is best?)

I'm taking a Powerscore weekend intensive course August 2nd and 3rd, going on vacation the week after for 5 days, then will come back to study for about two more weeks before I take the test. (Is this a good idea? I think it will be nice to take a little rest after all my studying, then come back fresh and work on any remaining issues the two weeks before I take the test).

I took a couple practice tests last time around and was getting about a 550 without really trying hard (took them at work, had interruptions, etc.), but my target score is low 600s (obviously I'd like to score higher, but I'm trying to keep realistic goals)

Any advice or help on what else I can do to do my best would be greatly appreciated.