I’ve got 2-886’s 1-887 & 1-678 all are good vacuums the dirt cup is nice you can see what you’re pulling out of the carpet the down side in the shop or large jobs they are impractical for us because they don’t hold as much soil as the 886. For this reason I prefer the 886 I’ve had one for nearly 10 years the other about 5-6 years all these need are bags belts, and pulleys you can pick a new one up on the net around 200.00 and every part like all the Sanitaire vacs can easily be replaced all are of can be shake out bags so no disposable bags
required.The 678 is giving us a little problem with the on/off foot switch but it's a cheap 140.00 Sanitaire
If you get a really, really good deal and want a cup model you can buy the part and convert it cost a 100 bucks or so to do likly its easier to just buy a 887 and be done with it .
http://www.vacland.com/sc887.php