Like you, I was a long time 240 owner and have worked on them for years, actually since the early 140 days. Two years ago I purchased a '94 850 Turbo Wagon and still get a grin driving it. The 240 series does not compare to the power, comfort, handling and features of the 850 series. That being said, they are not nearly as easy to work on primarily in the engine bay, as there is less room due to the engine/transmission layout. With a good manual, patience and the help of many on this board as well as Volvospeed's Bay 13, you can do a lot of work yourself. Their longevity has been questioned, however I think the jury is still out on that. There definitely are more expense to repair and if you're looking at an 850 Turbo, it came with an automatic transmission and that is a very costly item to replace. Search this board, as there have been many posts concerning what to look for in a used 850. Definitely have it checked out by a reliable mechanic who works on this model, not just any guy down the street. Inspect the records for oil changes, transmission fluid changes and the like. My own 850's (I have a '94 wagon and a '95 sedan, both turbo) have been pretty good for 10 year old used vehicles, but the '94 has been more solid and had fewer required repairs, so age is not always the criteria. Look carefully. There are good 850's out there.

Good luck!