I gave GMAT just 5+ months before. I took classes, but I guess it was not worth before you are totally ready for exam by yourself. It's like just going to grab some of the tricks.. at least it didn't worked for me.

I did the self study.. with princeton, kaplan, barrons and cliffs book. Math and essay are not that difficult, I did have to struggle with the verbal part till the last movement and I miss my target by few marks, as I couldn't meet my verbal part target. But lucky me, I got into the school I wanted to.

Anyways, good site like "beat the GMAT", can be excellent source both for GMAT and also for applying to school you want. Take you time, plan and the most important is to solve the problem within the given time frame. So simulation practice is the best way to keep in pace.

All the best !

Sampada