I have the Pfaff 4850 Coverstyle, which is also a Coverstitch. This is a machine which has been a workhorse, and does everything I want. I did buy a very cheap Singer O/L from Lidl, so that I could leave the C/S set up. I find that the Singer is fine...
Yes, it's noisy, and a bit fiddlier to thread than the Pfaff, but it has sewn everything from silk to denim, to upholstery fabric.
My first O/L was a Riccar, and that was used on every kind of fabric too. That lasted me for well over twenty years.
Jessie