You may want to read the following review:
http://www.boats.com/reviews/perry-design-review-hunter-450/
Having owned my 450 for almost 5 years I can give you some of my issues.
1. The anchor locker divider is prone to rotting. I repaired mine with some git-rot and reinforcing the top with wood members thru-bolted and epoxied.
2. Access to the impeller and anything else on the port side of the engine is a nightmare. I installed a waterproof hatch in the shower which allows easy access to that side of the engine. There is an article about this upgrade on this site.
3. Water can leak into the rear lazaretts and has no where to drain. I have not solved this one yet, but periodically especially if we have had allot of rain I will vacuum out the water with a wet/dry vac.
4. Some of these came with Fiberglass rudder posts. Apparently the company outsourced to had some QC issues.
Hunter offered to replace all of those boats with a new rudder with a stainless post. My boat was refitted before I purchased it, but that would be one thing to check. Probably not an issue with the 456 since they were newer.
That's all I can think of for now.