I've been doing functional ABS and ASA lately and had a couple very annoying warpage spots. One was a total failure. (We won't talk about the other 3 failures that were wet out-of-the-box Bambu ASA...)
The X1C is definitely nice, but the all aluminum-and-glass side panelling has a sometimes-unwanted side effect: thermal conduction.
The aluminum sides are so conductive that they do not allow the chamber temp to go above 40C, even after a couple hours of heat soaking the build plate at 100C before starting an ABS print.
Enter: One random bath towel. doesn't look like much but just covering the three sides with a thin layer means it's good enough insulation to get the chamber up to 50C now! And the ABS parts look better than ever- every C counts.
Interesting! I haven't had issues with ABS at stock temps in my X1C - 90C for the build plate - and I print a lot of large flat ish designs. I have had more trouble with PETG warping, and for HIPS I have to crank up the first layer to 110, then 100 for subsequent layers of it won't stick to the Engineering Plate with glue stick at all.
My chamber temps do tend to be a bit lower, since I have an exhaust fan hooked up the carbon filter fan output to vent outside since ABS and HIPS fumes are nasty.
But yes, I've found 10C or so can make a huge difference when things do go south, it just hasn't been an issue on my X1C for ABS, fortunately. Interesting to see how much a towel improves your chamber temps though!
Overall I love my X1C, one of the best decisions I made, don't miss my old kludgy FlashForge Creator Pro and all its quirks one bit.
IME abs is just better at "sticking" with good glue and proper bed temp than petg is, not sure why but I've had tons of petg just unstick and start to warp from that. (That was with college public printers though so abused pei sheets and wet filament was very likely...)
I also think the x1 was the best choice I've made in a while. Man this thing is productive.
All filaments are sensitive to surface oil, but PETG in particular super sensitive to any oil on a build plate, just fingerprints are enough, plain pei sheets you can totally clean with plain dish soap and water, makes a huge difference.
Oh yeah. I'm religious about wiping down with IPA every print and washing every few prints on PEI. I just haven't printed with petg on this printer yet, my experiences were at my college where you'd get 20 boneheads slamming nozzles into the bed, printing with way too high a temp, printing TPU on satin sheets and zero glue stick causing it to bond way to strong and literally rip chunks of pei off the Prusa plates... they were in pretty bad shape.