To each his own. Since I began hunting down bowen statues, ive found that there are just as many "grails" as sideshow. Try finding a chrome silver surfer or red daredevil, classic iron man, modern thor, classic cap, etc, for retail anymore. Granted, Sideshow marvel and bowen marvel are in different price points, but when a 14" bowen thor statue is selling for a few bucks under a sideshow PF and is getting harder and harder to find, you can't tell me that sideshow has more desirability considering that the edition sizes on bowen pieces are usually double or triple that of the sideshow edition sizes.
As for the base details and sculpt, of course sideshow is going to be ahead in this area. Youre working with a much larger scale, you are able to make it that much more detailed.