You know, not only do I not get Grateful Dead, or most of Zappa, but dare I say it, I think QMS are not much good either. In fact, I see more of Man in Nektar.
So there..... 
There is much San Francisco in the Man Band, but not the obvious bits!
The Steve Miller Bands' first handful of albums is where you'll find the Man reference points, not QMS. Yes, if you're a guitarist you can play QMS "Happy Trails" and spot the lick Micky has copped (much as you can playing the solo from Zappa's "Willie the Pimp") but for the overall sound, the Miller early output is a lot more telling. Mr Ace stayed with me after Herne Hill recently and, seeing my vinyl collection, asked for some of the early Steve Miller stuff for old times sake. If you have the "Revolution" soundtrack album (which given that QMS contributed "Babe.." and "Codeine" to this set rather than their own first LP must have been almost
welded to the turntable back in Tierney Road) you'll find all sorts of Man titbits - particularly the ending of SMB "Your Old Lady" which, not mincing words, is SO close to what became the Spunk Rock ending that Martin's eyes popped out and he put his hand to his mouth in an "umm..." gesture!
QMS were almost certainly a great live act rather than an recording band (any guitar-improvisation-based act share that trait to a certain extent), with some exceptions - the debut is majestic, Happy Trails is mostly live anyway, and bits of Shady Grove are worth a listen. Deke's take on Dino Valenti/e is spot on - ruined the band with his whining and other than a few bits of Chippo on the two albums he stayed around for after Dino joined, the rest is dross. Gary Duncan is a lovely guitarist and a perfect foil for Chippo (his solid style complemented Chippo's Bigsby-waggling antics beautifully) but the time had passed for QMS, and the relegation of Freiberg to bassist/backing vocals was the last nail in their coffin.
I love the Grateful Dead an awful lot but totally understand why some people don't. It's a Marmite thing again. But I truly do have sympathy for those that don't like them, mainly because I detest Steely Dan and nobody will buy that one at all. "Oh, you haven't heard the right stuff" they say. Actually, I've heard most of it and they only give up persisting when I say "Well, the first album isn't so bad - when they were a band rather than two tossers' egos and some hired help". So I have all the time in the world for those that can't find room for the Dead in their lives, providing a fair chance has been given.
But this is where I beg to differ - I am desperately TRYING to like Nektar at the moment but can't quite get it yet. I think it is the too-English-for-me lyrics that do it, which is why I went off Yes/Genesis/anything by Peter Sinfield etc quicker than Granada TV went off Peter Adamson. I think Roye Albrighton is a f**king brilliant guitarist, but have downloaded a few albums (thanks to Allan H and others for the tips) and can't quite find a song to cling onto. Certainly, there are moments of '69-'71 Man on the albums though, to be sure. It's all a bit too splashy and spacey for me with no good rockers to temper it.
I think this discussion might have revealed the true beauty of the Man Band - spacey as fuck when they wanted to be, but knew when to call it a day and throw in a Daughter of the Fireplace that people could stomp too, for good measure. Very few bands - US or UK - had that facility up their sleeve.