Those spots are especially good because it is consistant spring-fall. Smallies will feed in fast water without or nearly without any current breaks. Could be a straight, skinnier and/or shallower, somewhat featureless spot or a small chute with ridiculous current. Fish will get right in that stuff and like you stated Tim, they are often dinks. During the right time however the biggest fish will be there. The stupid shad and minnows love to go up in that current and use it like a treadmill and some of them become lunch. A lot of fishermen miss out on them though because they think the water is too fast or it's too shallow, or both.