I have two identical builds in 260 Rem and 308, Sako TRGs. I shoot to 1000 yards frequently. I find the 260 easier to shoot well (more consistent), much less susceptible to the wind past 600 yards, easier to spot impacts, and more fun to shoot. It seems to be in the sweet spot for accuracy, recoil, cost/ease of reloading, and barrel life. Shooting it suppressed is about as sweet as shooting gets, in my opinion!
My buddy shoots a 7mm RM with 168 Bergers at 3100, very impressive ballistics. The 260 does a pretty good job of keeping up with his 7mm at distance, with much less noise and recoil. He admits the 260 is very easy to shoot well. He has shot his best group ever with the 260, 5 shots in the .2s.
Here is a 100 yard target from the PTS Spring Match with 1 and 3/8 inch circles, center bonus target includes 1 inch circle with cross hair. I shot it in about 60 seconds under time pressure. Closest shot to center of crosshair on bonus card won a special prize (somebody center punched it). There was a left to right crosswind, and I could not see the holes in the black while shooting at 14 power against the berm. I don't think I would have been as consistent with my 308. If you have only shot groups and not dot drills, it is kind of challenging. This one was even harder because you could not see your bullet impacts. It can be pretty frustrating trying to be consistent. The 260 seems to be very repeatable and bucks the wind well at distance.
Go with the 260!
TKAB