Have you tried the DEROS 680CV? It's 66% greater orbital width (8mm) makes for much more rapid abrasion. Still uses the same Abranet or just about any other proprietary abrasives thanks to the multihole pad arrangement.
Works best for me with aggressive low grit-count abrasives, although I personally prefer the ceramic Abranet Ace HD which gives remarkably long life & goes down to 40G, but still offers Mirka's superior dust management.
As far as I'm aware, only Mirka markets the 8.0mm version, but both M & Delmeq market clones of the DEOS delta sander. I have the Delmeq version. I use both Abranet & Klingspor abrasives, but again prefer the mesh abrasives for the same reasons mentioned above. The DEOS Delta has a midrange orbital diameter of 3mm, which is approx. 20% more efficient than all the lesser rivals. Its larger pad makes it extremely smooth running, & its larger orbit makes it pretty efficient too, whilst still providing a pointed platen for those internal corners. A great all-rounder.
As far as the smaller delta detail sanders available, I still use a pair of discontinued Robert Bosch detail sanders, which have interesting & useful extended, profiled & slender platens & fingers for all those fiddly bits. Festool's Deltex was also another (discontinued) gem, too, but lacking in the versatility of the Bosch versions.
I found the F/tool RO90DX to be an evil, handling, unruly dog of a sander in comparison. Probably one of the worst sanders I've ever owned. I suspect others feel the same way too, as they're coming up "lightly used" in the classifieds with alarming regularity. Do yourself a favour & avoid @ any cost!
But realistically, a pair of DEROS & another pair of DEOS easily, comfortably & efficiently take care of almost all (95%+) of my abrasion requirements. The small deltas & big belt sander are really only unpacked & used for the occasional specialist tasks that the other 4 can't or won't accommodate.
