I have a Wadkins Bursgreen, and having double checked against Google images, it is a BZL. I haven't done the homework but there appears to be a BL as well which may have other differences but doesn't seem to have the bed cut-out that mine has to allow a full 9" swing. The bed length on mine is well over a metre - there may well be long bed Graduates but I have a feeling that the one I know isn't as long as mine.
There is certainly the advantage of mass and solid workmanship with either of these - a friend got a Graduate about the same time (15 yrs ago) as I got the Wadkins, and neither has given any bother. Both are on VFD's, mine came with one and a corresponding delta arranged motor, but I had to dismantle my friend's motor to find the star point, which I didn't find a problem but many others would.
The main downside of older machines which hasn't been mentioned is that the headstock thread is always something different from the M33 that modern lathes and chucks use. So a chuck backplate always has to be involved. Similarly faceplates will similarly require that 'non-standard' thread, or have to be bushed.
Reputation is based on mass market experience and I think the Graduate had a significanlty greater educational market penetration, so has a reputation built on shear numbers.
I can't pass comment on the swivel head - I did three excellent 18" diameter platters on mine and wouldn't really want to go any bigger. I do have access to machines at the local wood turning club that have such heads If I wanted but have never felt the need.
Come back or PM if you wnat any more input.
Rob