I am facing the same dilemma, but decided to get mine restored instead of replacing them. Restoration costs 1/3 of what a new hatch costs and would not require a removal and re-install.
I am going to go with Select Plastics, LLC: Marine Hatch Repair
The quote I got is $400 per hatch, which does not include new riser arms or dogs. I am about to send the first one in. I will report back, with pictures, once it is complete.
They provide an 18 month warranty and if you send them pictures of your hatch, they will tell you if they think it is worth refurbishing.