Quite a few PH's have seen mine and none have reported any bad experiences with others.  And they have guided people like Gerald Mcraney, Chris Dorsey, Tony Makris (who now uses a R8 almost exclusively), that Boddington fellow, and many others.  So what?
What I and several others can and have tried to offer is pretty extensive 
personal testimony about how the rifle performs in the field under a wide range of conditions.  In my experience with the rifle and in the experience of others who I know who use the R8, it doesn't jam, it is extremely accurate, it has superb ergonomics, and the best factory trigger I have ever used.  That is all based on extensive use of the rifle in a lot of different places and under a lot of different conditions.
It is a little like the 35 Whelen isn't it?  I can hear it waved off around campfires all over the world.  But when I really want to learn something about it and its capabilities, your posts are invaluable.  You have actual experience.
I have no meaningful current experience living with European gun ownership restrictions, though in SA each barrel is treated as another rifle.
What I do again have is significant personal experience travelling internationally with firearms.  Nothing I have ever owned but a double is easier to carry than a R8.  And I think we all have enough knowledge with doubles to agree they aren't quite as versatile as the R8 on the arrival end.  I don't enjoy dragging big wheeled cases with multiple rifles, and if one's destination has a charter plane waiting at the airport, the big case can become a problem for everyone.
I have other rifles and use them.  I will be bringing my .275 to Zambia in August to hunt PG with 
@spike.t.  But not because it is a "better" choice than the R8 with the 300 Win Mag barrel, but because he and I appreciate a Rigby.  I took my last whitetail a few weeks ago with a Bradshaw single shot in 7x65R.  It is a lovely elegant rifle that I truly love.
And everything is relative.  For the cost of either of those rifles, one can own a R8 and several sets of barrels - four rifles of extraordinary quality for cost of one.  That is almost the definition of a bargain isn't it?
The best, most dependable travel rifle, particularly for Africa where multiple calibers may make sense?  Based on my experiences, it is the R8 - hands down.