Oils are blended for specific applications. Cars do not have 'wet clutches' like motorcycles do. This is the big area of concern. The very finest, most expensive oil for your Ferrari could render your Suzuki almost unridable with useless clutch action. So you can take a chance, cause you know better than the manufacturer; or you can take the cowardly way like I do and go with only a 'motorcycle specific' oil.
Which one is best? It gets easier. There aren't any bad ones available. So no wrong decisions as long as you stay within your application. Frequent change is more important than splitting hairs about one being better.
Always used Shell Rotella T Synthetic in my bikes and cars with no clutch issues. 5W-40. About $13 at Wal-Mart for a gallon jug. Made a huge difference in sound coming from the tranny, much quieter. Just put it in @ the 600 mile mark.
The Mobil 1 for motorcycles is great, the Mobil 1 for cars will make many wet clutches slip, especially those bikes based on the Intruder 800 motor like your's is. I don't bother with full synthetic, as I figured out long ago that how frequently you change the oil & filter is far more important that what brand you use. I use a semi-synthetic most of the time, but if the shop is out of it or the regular dino oil is on sale I'll use that.
The clutch is an issue, not all bikes can tolorate synthetics.
If you do choose a Synthetic, you might want to wait untill there is a few thousand miles on the bike, for break-in. I went to synthetic's, at 7,000 miles, other owners, at 3,000 miles.