Love my 8.1L Suburban, but it sure doesn't compare to a good diesel. This summer we took a 4600 mile trip and the fuel pump went out in the Suburban 25 miles from home. Ended up taking my parents 2006 2500HD Silverado with the Duramax. No real comparison. My 8.1L goes any speed I want up most any hill, but it is louder and still has to down shift. Mine came from the previous owner with a K&N cold air intake. I'm sure that adds to part of the noise, I'd love to swap it out for the OEM intake but I haven't gotten around to looking for one. The Duramax in my parents truck stayed in 6th gear all the way to the west end of Montana from Michigan when travelling at 65-67 mph. Smooth and quiet all that way.
I have no regrets with the Suburban, but any older vehicle needs fixing up. Belts, hoses, fixing leaks, power steering pump, fuel pump, and on it goes. After having it 2+ years I think I finally have replaced enough stuff that it should be pretty reliable. Last year we went 3000+ miles out to Maine and back and it was trouble free until a loose connection causes us to get stuck in 2nd gear the last couple of hours. We have had a few issues with the fuse box due to the previous owners tapping into the fuse panel in ways that damaged the connectors. I think a fire dept. owned it in Georgia originally and had lots of electrical modifications.
For long distance searching, I used Autotrader, cars.com, searchtempest (multi citi craigslist search), ebay, etc. I liked Cars.com the best but eventually found mine on Craigslist I think using searchtempest. I live in the rust belt so I didn't want to find one close to home. It cost me $500 for a plane ticket, $50 for a hotel, and a lot of gas money to get home. About $750 total I think to retrieve it plus a day and a half. Not bad and well worth it.