I take a different approach to these guns. In my humble opinon, the older English doubles are the way too go. My reasons are:

-they are built to quality standards which would cost tens of thousands of dollars today
-from an investment viewpoint, they can not be beat. Several years ago I sold off my stock portfolio to invest in these. The return is very good, though they are not very liquid. But the enjoyment is far better than owning paper. A gun from a new maker will depreciate as new ones are being built.
-As Tinker mentioned, BPE rifles represent a fantastic value. I have had many from .360 to .577 and they perform extremely well. A normal .450 BPE with a jacketed bullet from Hornady (360 grains) will shoot anything short of buffalo or elephant. Compare the 45-70 to the .450 BPE and look at all the buffalo shot on the Western Plains. Read Sherman Bell's article in DGJ about hunting with a .577 BPE for buffalo.
-If you have ever shot a .577 nitro, it is not pleasant.
-Reloading smokeless for black is almost a no brainer with an abundance of reloading data available.

This is my opinion and sorry if I have offended those who opt for new rifles.

Read Ross Seyfrieds article "to own a double rifle" in DGJ Summer 2000. He is (IMO)the foremost authority on double rifles.
John