I had a chance to buy a 721 in .270 that was in "new in the box" condition but sans box, and I didn't hesitate. The 721 is, of course, just the "long action version" of the 722. To me, these old rifles include everything about the M-700 that I like -the symetrical action, the "three rings of steel" breeching, fast lock time, crisp "Walker" trigger, and so on, while omitting one of the the checkered and oddly shaped (to my palm) bolt knob.
I like the "all business" styling of the 721/722 also. Not so enthused about the blind magazine but that is correctible with M-700 bottom metal.
Aside from having a blind magazine, only downside that I can see with a 721/722 is the exctractor, and the only problem that I can see with that is that direct replacements are difficult to come by IF you break one. If one is broken, a gunsmith I know assures me that he could make a new one, modify the bolt for a SAKO or AR-10 type extractor, or possibly even modify it to take a M-700 part. The point is that a broken extractor need not end the rifle's service life or reduce it to wallhanger status.
Another pain that I ran into was minor and came when I set about mounting my 3-9X Leupold to the rifle. The leaf spring rear sight interfered with scope mounting. This .30-30 carbine-like sight is dovetailed into a "dog knot" form on the barrel. I simply removed the elevator from the sight, drifted it out, and re-installed it "backwards" or with the leaf extending toward the muzzle. This way, it doesn't interfere with scope mounting and I can mount the scope low, there isn't an ugly unfilled dovetail slot to spoil the looks, and I have a functional rear sight as a back-up, in case I ever need it.
I'd very much like to find a clean 722 in .222 Remington. In my view, this is the rifle that Remington built its reputation for accuracy on.
The 721/722 rifles aren't fancy, but they hail from an era when craftsmanship mattered and they'll probably do anything a new 700 ADL would.
JP