Unlike the Form 2, the Form 3 internals are not protected by a sheet of glass. So dust, spilled resin, etc. can get into the main chamber of the machine. On the flip side, that means it’s easier to clean that section.
Instead the LPU, which houses the optics, is now an independent, user-replaceable unit. This should do a better job of protecting some of the sensitive components, and make replacing them in one go dramatically easier should something go wrong. If I’m not mistaken, the printer parks the LPU in a location that provides some degree of shelter to the narrow optical window (which is a thoughtful detail).
There are still a lot of moving parts in the printer (I expect more than the last generation) and some - like the flexible tank bottom - are somewhat radical new innovations. Nobody knows yet how robust those will prove in the field. Some issues already presented with tank adhesive leaks, which were addressed in the V2 tanks, but still necessitate a limit to how long you can safely store certain resins in them. One or two users have also complained about contaminated rollers scratching or marring the bottom surface of a tank.
The Form 2 was a more iterative upgrade, where Formlabs refined existing designs on parts like galvos, etc. The latest model once again introduces brand new elements like the tank tensioner, new sensors, more linear moving bits, etc. They simplified some things that were finicky in the Form 2 (eg. switched to a more traditional float sensor vs. previous capacitive method of resin level sensing).
All that said, each time they release a new printer they incorporate lessons learned from past models. For getting consistent prints and maximizing printing uptime, I found the Form 2 to be a big upgrade from the Form 1 and 1+.
Since your beef seems to be with the degree of labour-intensive finework to maintain and repair, I actually think the Form 3 is potentially a really good fit for you. Most of the delicate cleaning steps like small/large mirrors, galvo mirrors, etc. are simply gone. In time there may be a need to lubricate gears (like the Z screw) or clean / tension / replace drive belts.
I expect the Form 3+ or 4 or whatever will one day iterate on the present design and further improve reliability (unless they finally come out with a new polyjet).
In terms of a 3rd party maintenance plan, have a look around where you live and see if there’s a good Formlabs reseller there. If you buy your printer from them, I imagine they’d let you simply bring it back to them when it’s having problems, and you might be able to negotiate more personalized repair/maintenance coverage when the warranty runs out. If that’s not an option, there’s always the Pro plan from Formlabs themselves (although I know someone on the Pro plan who told me once they were frustrated with the number of in-the-field steps they were made to do before shipping back their printer).
