I have had two 7.3's, a 1997 and a 2002, and they were both good engines, but they are not without their flaws, and high maintenance expenses. As far as rebuilding, the diesel heads all say "their" diesel will last them 300,000 miles or more. Maybe, but most don't for one reason or another. A rebuilt diesel engine, even a 7.3 will cost you 2-3 times what a rebuilt V-10 will cost. A rebuilt injector system or new HPOP will run you almost $2,000 alone, not to mention new injectors, glow plugs, etc. Alot of the earlier 7.3's had a bad habbit of quiting due to CPS and bad wiring just under the valve covers. Cummins have their problems too, especially cracked exhaust manifolds, bad injector pumps(and don't EVER run a Cummins out of fuel!!), and a host of other maintenance issues. Diesel heads are all sold on their diesel engines, but a good gasser will go as far without all of the major issues associated with diesel engines and with easier,cheaper maintenance.
2008 F-250 4X4 Lariat V-10
2002 Airstream Classic 30' w/SO #2074
2007 Kubota 900 RTV
1996 Ford Bronco
2007 Lincoln LT