I've been using my Balco 3D printer (via Aldi) for just over a year. I guess most of my efforts have been directed to custom enclosures of one kind or another. It has been a boon and a great time saver especially with multiples of the same part or where parts need to be modified as a design develops. Of course there are bound to be problems!
A number of things limit or frustrate me:
1. My skill at using various CAD programs. I'm pretty good at CorelDraw so I can draw almost any 2D shape using Bezier curves etc. I can extrude these into 3D using Design Spark Mechanical or FreeCad.. From there I can cut holes of various shapes and round and chamfer edges and corners etc. More organic and blended shapes I haven't attempted yet.
2. The quality of finish can be disappointing if you want texture free or polished surfaces. They require sanding and polishing which can be a pain with complex shapes. I haven't tried solvent smoothing yet. My guess is it won't be that good.
3. I've only used PLA filament so far. This is quite susceptible to distortion at quite low temperatures for example in strong sunshine or in proximity to hot electronics.
4. Of course, there will always be a limit to the size of a print (although you can often make your project in bits and glue them together).
5. Some shapes (with overhangs etc.) can't easily be printed without supports)
6. Printed dimensions are completely consistent but not completely accurate. Over the largest dimension that can be printed, the error is appreciable so has to be taken into account
Also, it would be nice to be able to be more spontaneous with designs. Perhaps to be able to try to be a bit “arty”. I've got a Polaroid freehand filament extruder. I would like to print something and then embellish it freehand but, so far, my efforts are crap!
Box for Raspberry Pi plus some additional circuitry.