I've shot a couple of 300 Weatherby's. They are by no means a beginner's rifle, but for me the recoil is manageable. If you have experience shooting other high-powered rifles and are not recoil sensitive then go ahead and get that rifle. Bullets will be expensive if you don't reload. Around here the cheapest factory stuff I've seen for a 300 Wthby was about $60 per 20 round box! A little too rich for my blood, but if it is not an issue for you then by all means go get it.
Of course someone will come along in a few minutes and tell you that a 300 Wthby is entirely too much rifle for a deer. My view is that as long as you can shoot it well enough to make good, clean shots...dead is dead.