I love the quarter bore, had 5 25-06's at one time, only 1 now. Also have 257AI on a custom Mauser '98 I built, it also has a 338-06 barrel, both having 10" twists, and have a 257 Bee I picked up at a reasonable price with only 60 rounds down the tube, it's an Accumark and shoots very well.
I really like the 284 case, have a 6.5 blank here with a 1:8" twist that has had a rough chamber job in 6.5-284 and not touched since, never got around to finishing it, even though I have a REM 700 it could have gone onto. I built a few 25-284's back in the day, as well as 30 cal.
I feel the performance of the 284 case is a worthwhile investment.
Cheers.