My last layout and my next will rely heavily on Marx 034 curves/switches, along with a limited # of low profile 042 K-Lines. The Marx can be a little bumpy, but IHMO not near as bad as Lionel 1122's (and no sparking, since they aren't auto non-derailing). Being powered separate from the track you won't burn one out parking a train on it, and they don't require a massive amount of juice to operate reliably.
One "must do" item is to add a guide rail on the turnout side, or derails will be constant occurrences. I use Atlas controllers in place of the original tin or plastic controllers.
034 switch w/ guide rail added
027 switch w/ guide rail added
The 27" switches are great to use as well - no clearance issues as with Lionel 1122's or K-Line's with the big honkin' switch covers - as long as you can live without auto non-derailing.
