This is one of those rings on/rings off debates.

I've heard they keep best factory sealed. That's what I've been doing with my tubos and I've been pleased with the results, although I don't have anything to compare to.

The only reason I'm aware of to open the tube is to accelerate the aging process. This is a moot point for me since I have yet to have a cigar survive longer than a couple of months in my humi.

The only way you're really going to settle the argument is to get a box of really good cigars en tubo, take the caps off half of them, keep them in your humidor for a couple of years, and then sample them. Let us know how it goes.