They work best for me starting pre-spawn until late summer. Hard to beat a Keitech, downside to them is that they are fragile, but I've never seen another bait out fish them. I like a jighead with a short shank hook, leaves more body free to kick. I like to pause the bait during the retrieve, let it fall, it will often get followers to bite. Edit: Keitechs kick real well on the fall, some swimbaits just won't kick that easily unless you fish them fast. Test them out by letting it fall near the boat where you can see it and look to see how well it kicks.
Great bait for bass, walleye, stripers, hybrids and whites. I'll usually go with a match the hatch approach as far as size.
When fall rolls around I don't get as many bites on them, spoons start to work better for me for shad chasers. Early spring I'll throw them right up on the bank, once post spawn sets in I'm out looking for suspended schools off deep water near cove mouths or off the bank on gravel points.