Here's who I used:
1985: San Leandro Auto Upholstery on Washington. Front seats on my Super, did a B+ job for $300. Don't know if they're in business any longer, but I was very happy.
2000 or so: Hank's Trim in Alameda on Eagle St. Did Super dash top, A-pillar covers, B pillars, and headliner in one job for maybe $300. A job; Excellent. Then all four Super seats, in good vinyl, including welding/rebuilding inside of driver's seats, which was broken, for $1400. Estimated job first at $700, then quoted $1100, then when I picked it up got surprised with final total. A+ job, but I was not so happy about the financial roller-coaster with no warning. Nowadays, I don't care. Great job. I would not have taken these seats to my current fave, see below.
Several jobs over the years: Jesus Angulo at Angulo's Auto Upholstery at 88th and East 14th (International Blvd) in East Oakland (in the back of an auto electric place). All four seats in my 74 GTV about 10 years ago, $300, B+ work; matches original vinyl really well. Mustang and Berlina small seat projects for $60 each, B+ work. Driver's seat of 72 Berlina and pass seat of 89 Graduate last month for $150 each. Graduate seat I'd give an A- to, Berlina a B-, but it is a difficult seat. Jesus is great for workaday cars, cars you're selling, or if you don't care about too much sophistication. He is in my experience timely, honest, cheap, and easy to deal with. I will continue to use him for the right projects.
No matter where you go, I'd counsel taking the hinges, brackets, etc., off and saving them, taking in the back and bottom as separate pieces. Upholstery shops, like body shops, especially cheap ones, are in the habit of losing all your trim and hardware and replacing it with whatever is at hand. I had to dig all my Mustang's unique hardware out of the garbage. You get what you pay for, mostly.
Now who can provide the same guidance on the affordable mid-level quality body shop we're all looking for?