I have a .25-06, and consider it a fine cartridge, right on the ragged edge of overbore, until recently that slower powders have come on the handloaders market.
never had any interest in the .270. Mostly because of (again, until recently) meager bullet selection. 130 & 150gr (and the 150 was a RN) were all the factories put out. Today, thats not the case, but all my needs and wants are already met without the .277 bore size.
My rifle collection covers .22, .24, .25, & .26calibers and then goes to .30 and up. I'm sure I'm missing a number of good shooting rounds between .26 & .30 but I only have so much time in life, and I don't even get to play with what I already have as much as I would like.
One thing to remember, don't take the published ballistics as gospel. Your rifle can be differnt. One good friend of mine had a .270 Weatherby. Used it well for a few seasons, happy with the speed and power he had over the .270 Win, (and many other rounds). Then he got a chance to chronograph his rifle an ammo (factory). He was getting less than 100fps more (avg) than the same bullet wt in a .270 Win. Quite a bit less than published ballistics.
He later sold the Weatherby, and went on to other calibers.