Hi, I would whole heartedly recommend the Phoenix 570 have owned mine about six months, before that I ran a maxx and I thought that was the bees knees at the time but the 570 is miles better with better heat more vacuum and running it on auto gas is a lot cleaner than the old diesel.
There's quite a few of us now running the Phoenix I dare say you'll get a few more replies, so yes if you want to upgrade liquid cooled is the way to go.