Unanswered Quality of 3D Printer

It is a combination of nozzle sizes and feed rates along with the accuracy of the drive components (how small can the steps be for each axis and how accurately can they be positioned).

Even with the stated accuracy of the Robo people have printed to that level of detail in the past.

See @tesseract threads on high accuracy (small) prints. He might also be a better reference for how accurate the printer can be.

 

it's time vs money. Most printers on the market can be hacked or tweaked to get down to 50 microns. Typically as you increase resolution, some print artifacts that may not be much of an issue at 200 microns, like ringing (a ghost image of a feature repeats across the surface) and layer registration (how well one layer is aligned with the next) become much more noticeable.

I have both an Ultimaker and a Robo and like both printers quite a bit for different things.

The Ultimaker uses very good components, has a design where the axes are all very well supported and aligned, and has excellent quality control. It also has a very light hot end. So, you can print relatively fast even at higher qualities. If you've looked at pics people post of prints made on UMs, you can see that a lot of people do regularly print at high resolutions on those machines.

Robo has gotten a lot better since the early days. I think it is an excellent starter printer, or even a regular use printer for large objects... as long as you are willing to put some work into tuning, maintenance (sometimes even brand new out of the box), and perhaps hacking if you really want to get the super high quality prints. However, it is about 1/3rd the price. So, again: time vs money

Note that there is a direct linear relationship between layer height and time to print. I.e printing a 50 micron print and then printing the exact same object at 200 microns with no other changes to settings will be 4X faster. So printers like the M3D micro and the Tiko that are dirt cheap, but dog slow are probably not printers you would even want to bother hacking to a higher resolution. The Robo is sort of medium speed; you don't want to print at 50 microns all the time, but it can do it in a pinch. Ultimaker is high speed, so it's fairly normal. There is also a new printer on the market, the Dynamo3D EVO that is about 3-4X ultimaker top printing speed, so that's one to think about too if you're considering Ultimaker.

If you're really planning on only printing high res all the time, a resin printer like the B9 or Form 1 may be an option.