The Vector is a good machine, but it's not really in the same league as the other two as far as the quality of wash it can deliver. Set up properly it can give a very good wash, but it's still an inverted L, no oscillating sprayers, wheel scrubbers, or the like.
As far as maintenance, again it's not in the same league. It has almost no routine maintenance, and it's very easy to service if you plan on maintaining it yourself.
Belanger has been great, but having a good distributor is very important. Any yahoo can cram the machine in the bay (Our Vector was hung 2 1/2" off level), but installing it properly, setting it up right and providing a thorough PM is extremely important. Talk to other operators about their units and find out who services them and whether or not they're happy.