Overall

It depends on how much you really want to improve your quant skills.

I have done a lot of quant / math in the past, and I have seen questions here I didn't know how to do initially, or where someone else has submitted a neater solution, or shorter solution.

So I found it helpful to get my speed up and just see if there were any tricks that GMAT assumes that I didn't have fresh in my mind. I also found the public correction aspect helpful. If you make a mistake posting an answer here you will be caught out. At home it is easy to forget about silly mistakes quickly, here your mistake is still on view the next day.

I got 50 on the quant with 12 minutes to spare. I maybe added a mark or two and saved myself 5 minutes by posting here for a month.

If you are getting say 30-35 on practice tests and aiming for 40 then this forum is maybe less helpful as the level is too high / too random here.

With tests like this, some people try and beat the test without having the complete skill set. If you want to get a high mark - and do well at business school when you get there - you need to actually have the skills to do the questions. There is no point in getting a high mark you don't deserve.

Perhaps my post wasn't clear. My point was that you shouldn't feel intimidated by the various questions that are offered here. The material is for the most part understood by the regulars, but you needn't be an expert in all areas. You still want to do some original thinking on the exam!

I feel the same as Richard, I put in a lot of GMAT quant preparation for probably a couple extra points. Most of the work was done years ago studying for various quantitative professional designations, and college exams, etc.