Why don't you go to the people who actually supply / manufacture the machines and try them out, as you will only get a true feel of a machine, by doing that.
All you will get here will be opinions and too many of these will cloud, rather than clear the issues.
Don't be too concerned about the huge variation in psi, and / or vac' power, as there are machines, with only 100psi and some with a single vac' which offer adequate performance, for moderate use.
robbie