My brother has a 270WSM and I have a 7MM, both in Weatherby Vanguards. They are nearly identical in every aspect - ballistics, recoil, weight, accuracy. The differences I see are a greater bullet selection in the 7Mag along with easier reloading. We have not had any feed issues with his gun.
I'm certainly no expert when it comes to reloading, but I've read that the short mags can be a bit tougher to get resized correctly. This has been my experience. Seems his gun just has a smaller range of acceptable measurements.
I'm probably in the minority here as a reloader, but I've been leaning toward the more common, traditional calibers - .223, .243, .270, .308, .300. You can find bullets just about anywhere as well as other reloading supplies. They just seem a little easier to get set up for me, and I don't want to spend a lot of time and money chasing an extra .25 - .50 inch of accuracy. For what it's worth, which was free.