It fits to such degree that opinions otherwise are down to personal tastes and sensitivity.
The finish and color of the Trail Loop's titanium parts are not a perfect match to the natural titanium Apple Watch Series 10 for example. The former is matte and slightly lighter in color than the latter.
If you run your finger over the corners of the watch where it meets the band hardware you can feel a slight ridge. I don't have sufficiently accurate measuring devices to measure it, but I'd guess the lip is around 0.15mm. The connecting hardware fit is snug as it should be. No jiggle, no wiggle.
Function and comfort-wise I find the Trail Loop and Sport Loop great.