I think the difference between the Rotex & the Metabo is like comparing apples to oranges. If you tried an ETS sander then 1 handed is effortless with them.
In saying that i have had a lot of problems with my RO150. The suction makes "NO" difference. I have tried every speed setting & suction setting but no different. I can be sanding 3 or 4 boards no problem then all of a sudden it just goes mental ! Its been back to Festool but they said there is nothing wrong with it. Bolloks ! The fact that this discussion keeps coming up proves that others do have this problem.
I have been using sanders professionally for over 25 years so anyone that says I'm doing it wrong is more than welcome to drive up here & show me the error of my ways.
But as others have said, i wouldn't be without it. When its behaving its the best sander ever.