I never experienced printing with 3mm filament. I decided to built the TOM using the 1.75mm kit.
So far I haven't run into many problems, except that I need to get a spindle/spool because it's pulling a lot more length than a 3mm filament.
I can also follow the end of the filament with another one without any issue, or discernible print quality change.
What issues or concerns do you have with the 3mm? I can let you know if I see the same issues with the 1.75.
- Jwo