I have a 2004 with QSM. Not much maintenance for us low hour lake users. The change from the older engine to QSM in 2004 required some hull strengthening. It was mainly under the rudder area if i recall correctly. Just make sure if you go to buy an early QSM powered boat double check with Formula. I think it was all resolved by 2005. Doesn't make it a bad boat or any issues after the repair. Mine had the repairs and its stronger now than prior year boats. Chances are all those boats have been fixed by now. Its not like there are 100s of them out there. Heck, I dont think formula made 60 of the 48s over the years.
We love the boat. Just wife, dog and I. Some may think its too big but I like it. Ride is great but we are on a lake not the ocean. Fuel burn for me is about 28 gal and hr at 1800 if i remember. Again on a lake, fuel burn is not something i watch. The front birth is nice, lots of storage, stand along shower is one of the best things. I can't really think of anything that is a total PITA to work on or do as far as regular maintenance or cleaning. The back platform goes down more on one side, i think that is common and would be my biggest complaint.
Since we overnight every weekend t/o the summer we like it comfortable. We replaced 2 a/cs 3 years ago when we bought the boat. Went a little larger in front birth and main cabin. 100 degree TX heat boat set on 78 when gone and it will chill quick and hold well below 70 all day if you want it to. There are 3 ac in cabin and 1 in cockpit which seems about worthless but the heat is nice in the winter.
Boat handles really well around the dock in my opinion. i have never driven a boat this big other than my 48 to compare. I just know i can put it just about anywhere i need to.
It really is a great boat for the money. Everyone who steps on board is complimenting.