This is just a general rule, there may be exceptions.
When trying to decide where to sit on a coaster, there is a lot of subjectivity as well as factors unique to each coaster. Some conventional coasters are better in the front, some are better in the back, some it is just different depending on your location, and on some it doesn't make much difference.
On inverted coasters (where the track is above your head), the front row is where you want to be. It's been my experience that it is significantly better in the front. One can speculate as to why, but I've found it to be true every time since their inception (was true on Batman at Six Flags Magic Mountain when I was a kid). Most of the time, it is well worth the extra wait, even if it is much longer. That is not always true for other types of coasters. If you can't get the front, or have and want to try something new, the back is usually the next best on an inverted coaster.
The most recent example I've found is Great Bear at Hershey Park (often regarded as one of the best IC's despite its age). The first time I went on it, it was quite fun. I sat in the back because I was riding with a friend who I didn't gather wanted to wait the extra few minutes. The next time I rode it with my wife and we sat in front...it was like a totally different ride. It was all new (and it had only been a few hours since I rode sitting in the back) and quickly became one of my all time favorite rides.
