Used to have heaps of sanders:
Elu 1/3 sheet & Festo RS3E & RS1C 1/3 & 1/2 sheet Orbitals, plus an old 1/3 sheet B&D "linear action" sander that wasn't really. Plus a Festo RS4 & Bosch GSS16A Palm sanders.
Couple of Bobbie Bosch(small) Deltas & a Festo Deltex
Couple of Festool LS130 Duplex Linear sanders, plus a swag of custom & OEM profiled bases.
Bobbie Bosch PBS 75AE, Kango Wolf 2424 & Festool BS105E kit belt sanders.
Mafell/Kress UX150 & Festo RO 150E 150mm dual action ROT(ary)/EX(zenter) gear driven sanders
Mirka DEROS ROS in 2.5, 5.0 & 8.0 diameters.
Mirka DEOS Orbitals in small, large & delta configurations.
Metabo SXE400 detail RO Sanders (70mm dia.) - no less than FOUR!!
Triton Random Orbital Sander attachment (for an Angle Grinder). Super fast, super messy!
Fein FSC 500 QSL sanding attachments. Absolutely useless as a sander!
As to what you want, need or (dare I say it) should get, well that all depends.... Time will tell.
I've refined my own collection down from the rather ridiculous 2 dozen odd to a much more rational 10 for my own SPECIFIC NEEDS.
The old Festo orbitals were good, but also fairly slow: a common characteristic of all orbitals. The Elu eventually wore out. Orbitals are useful for fine flattening, & especially good at fine denibbing between paint & lacquer coats.
My small Mirka DEOS serves this purpose well, & takes the same size paper as the Festool Duplex & RS400 & the Bosch GSS16. My only orbitals are now the small DEOS 80x133 & Delta. Probably the Delta only would suffice at a pinch. The Mirkas are simply a better sander, having a larger (faster) 3mm orbit, lighter weight & superior balance to all others. The larger DEOS with a plasterer's shaped & sized pad eventually just became surplus to requirements.
Detail work is undertaken by the 2 Bosch Deltas (PDA240 & GDA280), which I prefer due to their system of extra sanding fingers, custom profiles that I've made & louvre extensions, which is why I still use 2. The tiny Metabo SXe400s are gems, allowing fairly fine concavities & complex mouldings to be smoothed & polished (i.e car headlights etc) in places any other sander can't. Which is why I keep one only spare. These were also ideal tools for the tiny hands of my young children, which is why I only retain a couple now.
The Festool Duplex LS130s proved utterly hopeless. Worst tools (with the possible exception of Festo/ol's execrable cordless drills) that I've ever owned. Despite dual counter-rotating counterweights, they're simply too vibratory for extended use, clog papers like a mo-fo, & their profiled bases literally crumble into uselessness with alarming & expensive rapidity. Just....don't. A hand block is actually faster!
Belt sanders have been reduced to the one big Festool BS105E. With its fine belts & its fabulous sanding frame fitted, it's uncharacteristically smooth & fine, or as aggressive & rapid abrading in coarser grits as anything other than a dedicated floor sander. I'd probably still have the small Bosch too, but for the fact that it was nicked. A belt sander will do everything & more that any Rotex sander can do, but much smoother, easier & faster. Provided the sanding frame is fitted.
As you've undoubtedly noticed the Rotex tools can become a bit of a handful at times, & must be firmly gripped & carefully guided. A belt sander doesn't: its own mass & inertia does the work, requiring the lightest restraint but no pressure, but its speed & power means that it, too, must be kept in perpetual smooth motion over the substrate.
As far as random orbitals are concerned, I've found that the Mafell/Kress & Festool Rotexes are just a bit too big, heavy & rough for my ageing hands. As you've already noted, they're a bit too rough to provide a fine finish. The Mafell was rubbish (too much power for the relatively weak geartrain), & when I "found" the Mirka sanders, everything else simply pales in comparison. Less than HALF the weight of the Festool (maybe 1/3 of the Mafell!), smoother running and far superior results to any other I've tried. So good, in fact that I've personally found the 2.5mm diameter DEROS to be redundant.
I think the difference is in the papers: Mirka's Abranet mesh abrasives are just fantastic. To be fair, though, maybe a but too susceptible to tearing on sharp or hard edges. But so are paper-backed abrasives too. The Abranet ACE & HD abrasives are super long lasting & (incomparison to Festool's range) fairly inexpensive. Dust extraction through Abranet abrasives is in my opinion unequalled. Plus the huge number of holes in Mirka's sanding pads means that just about any other rogue abrasive will work & extract well too.
Don't think that I'm unneccessarily down on Festo'ol's sanders here. They're all (with the exception of those stupid LS130s) good tools, but the world has moved on a bit in the past 40-50 odd years since they were originally designed. Whilst Festools are good, Mirkas are great. Where Festool's products often prevent anybody else's pads & papers being used, most others use common mountings, hole patterns & readily available sizes. If Mirka's sanders seem a bit too expensive, then one of their licensed clones (Indasa, Rupes, Carsystem, Metabo, Delmeq or Sumaki) which use the same hardware will possibly save you a bit.
My single remaining Festool sander is the BS105E, mainly by virtue of its sanding frame & commonly available belt sizes (for which I actually had to shorten the distance between the rollers). It even takes Abranet Ace belts. Since Festool Australia sacked my 2 preferred local agents & repairman & gutted the retail network, it's near impossible to access regular consumables, spares & parts in a timely fashion. The last straw for me was an over 3 month wait-time for a basic delivery of some abrasives & a replacement pad for one of my Duplexes. My nearest Festo "retailer" doesn't even stock the flamin' products: thety just order 'em in as required/prepaid. Blow that for a joke!
So the 4 Mirkas, 2 Bosch Deltas, a brace of Metabo detail randoms & the big Festo/Holz Her belt sander now comprehensively serve just about each & every one of my (unique) sanding needs.
You will undoubtedly require a different suite of abrasive tools.
P.S. Just remembered that I also (shortly) owned a RO90 DX kit from Festool too. This ridiculous excuse for a sander probably ties with Metabo's Porsche Multihammer as one of the worst designed power tools of all time. It was just terrible, & more than any other has probably turned me away from "modern" Festool designs for life.
