Hi
I opted for an X1 carbon last year, and have not regretted it.
I have only had one print work out badly.
It was an ASA print of a long bracket, which lifted from the bed at one end.
ASA is known for it.
It was usable but not good enough for a customer.
I have mostly been using 0.4mm and these days 0.6mm nozzle as I tend to make structural parts.
Rule of thumb keep your layer heights below 50% of the nozzle width, this helps to maintain decent layer adhesion.
My favourite filament in the last year has been ABS-GF. It has excellent dimensional stability, tends to stay flat on the build plate, and has a great look.
You can operate the X1 without going through the online server.
I did see the black friday deals offered by Bambu were pretty good.
Many people review the P1 enclosed version as a superb printer for the cost.