Some years ago - after my first buffalo hunt - I had convinced myself I needed a double rifle. I looked around, but had a hard time making up my mind. And that was a good thing . . . because I eventually came to the realization that a double gun is a very specialized piece of equipment. One txt I would likely only use when hunting buffalo or elephant. And how many of those hunts would I go on? Not many . . . at least when it comes to elephant!
So I decided to take a portion of the money I would have spent and get myself a fine, custom made bolt action rifle, with superb exhibition grade wood, a Mauser action and lots of bells and whistles. And lo and behold, I spent far less than I would have on a nice double, and I had a gun that would be far more practical. Since that time, I've picked up a a few more bolt action rifles - including a Martini (of Heym Martini fame) and a Rigby, all beautiful guns, and all of which I can take with me and actually shoot.
And I'm much happier as a result.
Now, if you're going to be a PH, and rarely (hopefully) have to fire your weapon, by all means, a double rifle is a great charge stopper. But if you want guns you will actually carry and shoot, I'd say go for the bolt action. But get a nice one!