I have the womans kokatat goretex drysuit and I decided on the front zipper for a few reasons.
1. All the girls I know around the FR have the front zipper
2. I have heard many people complain about sitting on the zipper and if you are planning on kayaking, then the zipper digs into your sides where your hip pads are as well, ouch!
3. less zippers= less chance of water coming into the suit.
Downside...the boys will tease you because you have a "strap on"
either way the drysuit is awesome!