I was in the exact same boat as you this year. Much loved Metzler just couldn't hold air anymore regardless of number of patches. Didn't want to spend the dollars on a Hypalon boat and when I started reading on the PVC boats it seemed that most are made at the same factories in Korea and just branded differently. Supposedly zodiac's PVC seams are better than something like Saturn's but then again when I priced it out they were significantly more expensive also (like $2000 Vs $3500). Went with a Saturn myself and I'm happy so far but that doesn't mean much with only a season under my belt. It'll be that 5-10 year mark that will tell the tale. When reading a cross section of reviews I didn't really find anything glaring bad in any of the main PVC boat brands like sea eagle, seamax etc.
Some general info
http://inflatableboatworks.com/?p=1796
Good luck