Growing up reading Warren Page left me with a positive attitude towards a long belted case that drove a 7mm 160 gr Partition on the far side of 3000 fps. While I have no experience with the 7 WSM, I have put enough rounds through a 7 mag Remington to have an opinion and my opinion is positive. Recoil tends to be mild, trajectory is flat, versatility is high, accuracy is excellent. Its handloader friendly, and there are enough bullets choices available to result in severe information overload. I prefer long cartridges to short, although I get that the accuracy buffs like short and fat, as might those who prefer to carry a short action mountain rifle. Perusing the pages of one of the more popular loading manuals, it appears that the WSM requires a few more grains powder to match the velocity of the Remington, which might be what's behind the barrel burner claim, although I doubt that the difference in powder charge weight has much effect on throat erosion in the real world. But one of the reasons I prefer long cartridges is that when long bullets are seated, less powder capacity is lost in a longer cartridge compared to shorter cartridge. Short action rifles require bullets to be seated deeper than long actions, if the cartridge is to be cycled through the magazine, so if one was going to load say a 180 gr VLD, a longer cartridge, in a long action rifle, would have the advantage.
I think the beltless cartridges that have appeared over recent years, such as the WSMs, the Rugers RSMs, the .375 Ruger, and Remington's Ultramags, both the long and short versions, provide a small advantage over their belted counterparts. A belt interrupts the smooth surface of the cartridge, and opens the potential for feeding issues; although a feeding glitch due to the belt I believe would be, and should be pretty low on a potential buyers list of concerns.
Some folks are concerned about the feeding reliability of cartridges with rebated rims, and the WSM's rim is slightly rebated. Having fired several thousand rounds of .375 Ultra, I can say with some authority that there is little need for concern over the feeding reliability of rebated cartridges, even though my rifle certainly showed a preference for the cartridge to be located as far forward in the magazine as possible. It was possible for the bolt to slip past the rim when the cartridge was against the rear wall of the box, so it became my habit to position the top round in the magazine so the bullet nose is against the base of the feed ramp. One of the nice things about the .375 Ultra is that the first shot automatically positions the remaining rounds in the magazine.
If I was in the market for a 7mm magnum, the chances are that it would be the Remington version, unless I felt the burning desire to wildcat a 7 mag from a .300 Winchester, but the advantage would be somewhere between slight and non-exisitant. I could be persuaded to purchase a 7 WSM, but it would probably be a custom rig built on a long action with a long throat, but seeing that I'm about to enter my .280 Ackley phase, that could be some time in the future.