Belt sanders are amazingly effective @ converting wood to dust. A Rotex isn't bad either, but is really meant for different tasks.
I've used quite a few Belt sanders over the years, and actually owned a few too. Some really good 'uns are Makita's 9403 & the Bosch 1473 DVS, with a combination of 24 or even 36 grit abrasive belts, 1200w, and the big platen that 24" sanders use these can really abrade. The latter is one of the last genuine USA made heavy duty tools, now sadly discontinued, but still readily available in a variety of used condition/s. Only a dedicated floor sander can remove more. For levelling rough slabs, even board & parquet floors they're fine, but for anything approaching finesse they leave quite a bit to be desired.
Smaller belt sanders are pretty good, too. Much, much easier to handle and decidedly less aggressive too. Still more than a 6" (152mm) Rotex, 'though. Most 3" or 75mm versions are quite OK for grits =/>40, with the added advantage of being sufficiently light and controllable enough for vertical surfaces too. A veritable herculean task with a 4" belt sander. Lower powered motors usually preclude effective use of the very coarsest grits. Bosch has been making a great 3" sander for years now: my Swiss-made version has been running reliably for almost 40 years now, requiring only brushes, a couple of replacement "schleifunterlage" (platens), a handful of multi-V drive belts, and a new belt tracking adjuster tension screw. It has abraded literally acres of hardwood over the years: floorboards, slabs and glue-ups. A whole house worth, in fact, of home made Nothofagus and Acacia flooring, skirtings & archs, even V/J lining and ceilings!! Its 600w motor is however a limiting factor in its effectiveness: more power and more finesse are both sometimes required.
The addition of a schleifrahmen (base frame) to a belt sander aids finesse immensely. None do it better than HolzHer's now extremely aged designs, effectively unchanged for the past 50 years or so. Their 900/1000w 3" x 21" (75 x 533mm) & 4" x 24" (100/105 x 610/620mm) designs are still in my opinion class leaders & held in almost universal high regard.
So much so that when Tooltechnic's acquired the business a few years ago from Reich (HolzHer's parent) these were one of the very few original Reich designs carried over (the Symmetric was I believe another), without so much as changing a mere plastic moulding or screw! Is that highly regarded enough for you? The only change/s were to their livery, bringing it more into line with the Festo/ol corporate image, given that they were already a reasonable cobbled-together fit with Festo's dust extraction "system". Of the 2, it's definitely the smaller iteration that's the gem. At one time (prior to Tooltechnic's takeover) Reich actually manufactured or licenced most of Germany's 3" belt sanders: AEG, Milwaukee, Atlas Copco, Metabo, Wuerth, Wolf, HolzHer (obviously) and even Bosch (originally) were Reich manufactured designs. My own particular version is badged Metabo, which I consider to be the best, merely owing to it's (uniquely) removable front handle, relocatable on top for those tricky vertical surfaces. Think in-situ architectural mouldings, lining boards, boat hulls etc.
Shortly after acquisition, Tooltechnic cancelled all other build contracts for badge engineering. The alternatives offered by all these other manufacturers formerly using Reich manufacturing are little short of being utter rubbish! Some are even worse.
What is telling is that these were all 3" sanders. As far as I'm aware nobody else either licensed or badge-engineered the 4" version, despite its obvious strengths. Ever. I quite like my own Festo/ol BS105E. At 1400w it's a raging beast. But when using its variable speed electronics and with the schleifrahmen fitted it's can also purr like a kitty cat. Power AND finesse in the one package.
In that regard it's unique. In terms of its other "normal" belt sanding duties, its probably the equal of the top-of-the-range aforementioned 4" x 24" Metabo & Bosch versions. In fact from an ergonomic viewpoint either the bigger Makita or Bosch are possibly superior in their handling than the large Reich/HolzHer/Festo/ol by virtue of their fore & aft handle arrangement being less further spaced apart. The Festo/ol suffers from having wide spacing, which can get tiring in extended use in comparison. Its harder to maintain an extended firmly-held stance with one's hands spread far apart than with them closer for heavy duty sanding sessions, like floors etc. That rather ugly front knob, despite being slightly "textured" can also get a bit slippery from the sweat induced from hard use too. As you've guessed, I'm not a great fan of these particular fixed front knobs. The big Bosch loop handle and Makita's more ovate and more natural handgrip-shaped knob just seem more comfortable to me.
However, as an all-rounder, either of the Festo/ols are probably better. More power than the competition, those fabulously well-engineered, superbly performing removable base frames, and (now) access to the industry standard 4" x 24" belt sizes too. What's not to like?
Just the prices actually. At over Au. $1000 for the littl'un & the best part of $2K for the biggie, you'd have to be almost certifiably nuts to buy one new. That's about 3-4 times the price of the Pro. Bosch 3" & Makita 4" equivalents. Save yourself a king's ransom and either buy the alternatives or a well maintained second hand example of the HolzHer or Festo/ol "originals" or one of their multiple badge-engineered clones.
I've acquired my Metabo 3" version & Festo 4" second hand for about Au $150 & $500 respectively. The latter required stripping down to exchange the $50 belt tension Y-frame from the Euro standard 620 to the more universal 610mm (24") version. Each has performed flawlessly for the past 15 years +/-. So for me second hand was the smart buy. It would've been unconscionably extravagant for me to have considered a new buy. Do yourself a favour and do likewise.
