Both good rifles. I still own a Terrus. Very straightforward to strip down and you might want to check the finishing of the spring end. This fault manifested itself on mine with an occasional buzz on an otherwise very nice shot cycle. The 900x benefitted from an increased length of M3 trigger screw. You'll have to custom fit this as too long a screw gives you a hair trigger, but I seem to recall my M3 ended up at about 9mm long. Enjoy your pressies .