Not much difference between the major brands, but for high mileage vehicles, i ALWAYS use 20w - 50, it seals the pistons and prevents smoke... Good for older engines.
My friend put her 1994 Virago into the shop to have the starter repaired. This was an authorized Yamaha repair shop. When she went to pick it up, they claimed that they put in a NEW kind of system, and the battery would have to be hot all the time... Anyway, the starter just spins for like 10...