A plane with low hours requires MUCH CLOSER attention regarding pre-purchase audit (
www.skymaster.org.uk has a whole section on pre-purchase; just click on "Archive Specials #1 Purchasing Info").
I agree with Skyking that there is a "sense of pride in ownership of this particular piece of unique centerline thrust equipment" which leads many owners to super-care for their planes. BUT, for those who chose it because it's the cheapest twin around, you often find that the owner also skimped on maintenance, so many Skymasters are in very poor shape, with bad maintenance and worse records. So be very selective. I've bought from BOTH extremes: first a super-beat-up-with-no-records aircraft (which I picked up for a song after exhaustive research to re-create the lost records, and then spent lots of money fixing) and recently a cream-puff.
Engine overhauls range between $10K and $20K. Before others jump in to say my $10K figure is way too low, let me add some caveats. If an engine has had most of its accesories (alternator, starter, fuel pump, etc.) overhauled within the past few years (and some like magnetos probably needed overhaul to meet ADs) and you can find a shop to do the bare engine and it doesn't need a VAR crankshaft, then it can be done (I've done it -- for even less than $10K).
Good luck.
Ernie