I bought one about five years ago and have used it heavily since that time. It does a great job of thicknessing boards and leaves a surface that needs little if any sanding depending on what the project is and what finish will be applied.
I've sharpened the knives at least twice and find that process saves me considerably over buying throw-away knives that some of the other brands use.
Having said that, you need to consider how much you will use the planer before buying one (especially if you intend to buy a new one). If you buy all (or most of) your wood rough cut you will appreciate the savings. If you will only use it occasionally you may want to consider buying used or (some heresy here) buy a benchtop model.
Just some food for thought.
Added 8 Aug: I built the stand for the Shopsmith mount planer so it is exactly the same height as the way tubes. That way I don't have to lift the planer at all - just slide it from the stand to the way tubes and fasten it in place.
La Vernia, TX
Wood Goods - Custom Woodwork
EMAIL: woodgoods "at" lavernia "dot" net
PowerPro 520, PowerPro 500 (was my father's 500), SS jointer, SS Mark V mount planer, SS bandsaws (2), belt sander, scroll saw, SS jig saws (2), strip sander, Jointech system, 12" Delta Compound Miter Saw, a small collection of routers, a router table and a Delta Unisaw. All in a 24' x 24' shop.