I have road ridden with Speedplay Frogs for over 60,000 miles so I believe I can speak with some authority. I love 'em.
They are easy to enter and release, never release inadvertently and have the float you've learned to love in the X-series. They are also lighter than nearly any other road or MTB pedal.
The old-style Frog cleats require a small amount of surgery on the cleat pocket to fit most MBT shoes. (A Dremel tool with a sanding drum is ideal for this.) The new design is narrower and should fit nearly anything with no modifications. In fact Speedplay says the new design can be used with road shoes, but they obviously won't be walkable that way.
My favorite shoe is the Shimano SH-T090 (the current version is SH-T092)which lists at around $90. They are styled like a road shoe and have a flat, but quite stiff, rubber sole with a recessed cleat pocket. They aren't as "clunky" looking as fully lugged MBT shoes but are very walkable
and keep the cleat off the road and floors.
I also like Performance's house brand MBT shoes and these will take the old style Frog cleats with no cutting. They happen to fit my feet well and are less expensive than the Shimanos if you catch them on sale. However the sole is "real" MBT.
The only downside to MBT shoes is that they are slightly heavier than their road going counterparts. This isn't a big issue for touring or non-racing use.
This message was edited by DaveB on 1-15-04 @ 8:27 PM