The Revox are great machines. Very well and simply built, there are very few things that can go wrong. No belts to worry about as they all have direct drive motors.
Which version of the A77 did you get? There were MkI, MkII, MkIII and MkIV. The MkIV are the latest in the series and newest machines that can be found. These are also the more expensive ones as they are newer and (perhaps better) and typically in better condition.
I am afraid that $440 is a bit much for that deck, unless it is in absolutely excellent condition. Also, if it is a "pro" version with high speed (7.5/15ips) and two tracks, because of their semi-pro nature and better sound they also sell slightly more and that can explain the price. Other than that, these decks seem to sell at eBay at prices from $100 to $450, all supposedly in working order.
Did you buy it from eBay? If so, did you buy it from wneigh2222ol8?
If so, then this is a MkIV version, and it may well be worth the money.
There are several things that were improved in these machines, most notably the break mechanism. In the course of the machine's life, one of the "modifications" in the break system was actually a total redesign of it. Comparing pictures of the old break assembly with the new one, it almost appears that the old one was ill-designed - hence the comment from goldear regarding stopping the FF/REW operation before going to PLAY.
The MkIII and forward all had the new version of the break system, which is good. The same designed was carried forward to the B77 and PR99 models.
You can check a number of sites for information about these machines and there are all the relevant service and operation manuals online at studer's ftp, so avoid buying any.
Check out this site in the meantime:
http://www.theimann.com/Analog/A77/Versionen.html