@twister6: I've got VSD3S and echo your bass impressions - rounded / slow. I get good impact with single bass drum hits, but when they really get going it gets muddied. Sub-bass performance isn't there, either. Never heard the IM50 but am curious how the rest of the IM50'sound sig compares. Maybe you could provide a quick shootout for VSD3(S) vs IM50?
Already did a quick VSD3S vs IM50 comparison about a week ago: http://www.head-fi.org/t/669510/the-new-iem-of-vsonic-vsd-3s-impression-updated-by-smailbz/1905#post_10706898