Personally I see absolutly no drawback to them at all. IMO, there are far more advantages to them than there are disadvantages. More and more rifles are being chambered for them, More and more factory ammo is being loaded for them. They are becoming more and more popular so they won't be going anywhere as far as I can see.

I am just about finished building my own 300 WSM for myself. In about a week I'll be able to take it to the range. I can't wait!!!!!