Oh, here we go again. Here's my thesis:
I use Rotella T6 (5W-40), mostly becuase I use it in all my trucks, so it is convenient to have one type of oil. Oils have varying amounts of reserve alkalinity, known as TBN. Either Rotella or Rotella T6 have particularly high TBNs, so assuming good filtration, they can be run longer without building up acidity. I go 10,000 miles or one year on the trucks, and about 5,000 or six months on the VN750. I tried Rotella T (15W-40) but had problems with oil pressure when cold (55 degrees) and had to burp the filter on the side of the road several times. I must have something not quite right in the oil pickup line, like a small leak, or maybe with the oil pump.
The Bosch, Motorcraft, PowerFlo, ProLine, Purolator Premium Plus, Purolator Pure One, Quaker State brand filters use the same (best) filter media but varying amounts of it, and perhaps different anti-drainback valve design and material. The best of these (that I have seen data on) are Purolator Pure One and Bosch. I believe the SuperTech filters from WalMart use a similar media, buck much less of it- I will use those in a pinch (there's one on my bike now.) From memory, use the Mazda MX-6 filter as a cross reference-- it is a longer filter than stock-- check it out to be sure.
The bottom line is that it doesn't matter that much as long as you use a motorcycle compatible oil (NOT "Energy Conserving,") and change it regularly and before the reserve alkalinity disappears. It really depends on how the clutch and transmission work with the oil you choose-- every bike is a little different.