We have a VMC500. It was acquired before I started here (1yr 3mos ago) so I don't know a lot of it's history. It has proven to be a workhorse for us. We have had some air hose problems and some problems with the adjustments on the head.
The hoses were troublesome at first as they are metric. But we found SAE hoses that were close enough to work. Just a tight fit.
The head adjustments (sensors) was caused by a cylinder that had rotated to a point that the sensors could no longer see it. After me spending a few hours trying to get them adhusted a local (Orlando) repairman finally found the problem and put everything k in place. No problems since.
In my opinion, the biggest concern would be finding replacement parts and knowledgeable service if/when needed> I wouldn't expect that to be very often.
I don't know if I can offer anymore, but if you have other questions, let me know!