At present we have the Ampex 351-2 (updated), the Studer, a very nice Sony (allows you to change from 1/4" to 1/2" tape in seconds), an Otari and a Tascam.
In the past I used to do a lot of the on-location work with a Magnacord, a nice tube machine that is excellent but does not get much mention.
Mike is right about the rather crude setup of the Ampex 350 transport (we also have a 300 transport and things are no better with it). When I did the update/upgrade of the Ampex I chose the AG-440 transport. At least it has automatic head lifters! It also has a flutter idler in the headnest.
Years ago I did a recording of a large choral/orchestral work called Canto General. Mikas Theodorakis was in town to conduct, so I didn't want any screwups. So I used two tape machines, the Studer A-80 and the Ampex and made two master tapes. In playback the Ampex could use either tape and was obviously more musical than the Studer. The Ampex-made tape also sounded better on the Studer than the tape that it made. Both machines were in good condition and this was in 1986.
Now the difference I heard was one that is often described as the difference between tubes and transistors, so if you prefer transistors you may well have liked the Studer's tape more. I have to say- it was/is damned impressive.
The biggest weakness I have heard in tape machines is actually in record mode- transistor machines are prone to a certain kind of modulation noise that shows up most in simple passages. This is due to the head driver transistor being sensitive to the bias signal- special traps have to be used in SS machines to reduce this problem. Tube machines are immune.
So if you are in playback only IMO you have greater flexibility about which machine is the 'best', however it will certainly be a mastering deck unless somebody has really tweaked the hell out of a lessor machine. BTW the mastering machines respond really well to such tweaking. We have replaced every chip and coupling cap in sight in the Sony and the results were spectacular.
