Personally, I cannot deal with pressfit drive units. This is because I change engines often. To accomodate the engines' different rpm range, I need to change roller sizes. I do not have a press, so removing and reinstalling noisy bearings and different rollers got to be too expensive.
BMP uses a slip fit on the bearings' inner and outer diameters. I figured that if it was good enough for this vendor, it's good enough for me.
This is not to say that my slip-fitting the Staton friction rollers onto a BMP friction drive unit is the right way to do it. It works well for me because the bearings and roller are removed and reinstalled in the time that a good swimmer can hold his breath. There are no labor costs involved so that's a plus.
I can still remember the times that I tried to R&R the roller and bearings out of my Staton friction drives. It was an expensive and a labor-intensive chore each time I did so.