I absolutely love my 243AI and 280AI. It's a more efficient design. It's provides more FPS on the base cartridge, much better case life and a cool factor. The gains are very apparent even when done on a "shorter/sporter" length barrel. It's great way to "Freshen up" an older chamber. It's not for everyone, but it's great for me. It's makes the most of the platform you have without having to step up into the next higher case size. I have never had any feeding problems or any other complaints to speak of.
Here is a scenario: 2 hand loads off a 280 case with 140AB and a 200yrd zero 280REM @ 3000 and 280AI @ 3200
To a shooter taking shots out to 300 the difference is negligible, about an inch. Now stretch that to 600 yards and the 280AI shoots 9" flatter and carries 200ft lbs more energy. For the 1000ft lbs recommendation for taking deer sized game, the 280REM will get to 680, while the 280AI will get to 780 before dropping below 1k ft lbs of energy. It just depends on the shooter and his environment if it's worth it to him.
Savage88, You don't see the value in it because you are still shooting factory ammo. When you start reloading you will open yourself up to a lot of great options that won't require you to go to a higher case size to get more power. With the scenario above, you get almost 7MAG performance with less powder and recoil.