If my Sportster is anything to go by, there is not much point in looking in the mirrors as you only get a good view of your arms, especially when I'm wearing my waterproofs.
Although I love that bike, its the usual Harley triumph of form over function - putting big mirrors on long stalks like my CB750 would make them work much better, but wouldn't look as cool as small teardrop shaped ones on short stalks.
Its the same deal with my 2 gallon peanut tank - it looks way better than the large touring option, but is something you start to regret when, say doing the North Coast 500 in Scotland, especially on a Sunday when some of the petrol stations are shut. I went on it to a bikers do in Bethesda, Wales, this weekend - it led to an interesting encounter with some of the Outlaws MC when I limped off the A55 on reserve to look for fuel. To be fair, they were very helpful in pointing me in the direction of the nearest petrol station.