Well, I take back the "nobody has complained" thing after looking at AOPA's airport page and comments...
"Charged $43 to park a Cessna 172 on the ramp for an hour - Wow! Be advised that Signature has taken over the former Landmark Aviation FBO at KSAF. They have also instituted new fees. I stopped for a burger on Sunday and, because I didn't need any fuel, was charged $35.00 as a "Handling Charge" and an additional $5.00 "Infrastructure Fee." They also tacked on an 8.325% "State Sales Tax." Of interest, NM does not have a state sales tax. There is a state GST, but it is only 5.125%. No doubt, they added in a local tax. In any event, that's an inordinate fee for such a small plane for such a short time. The airport only charges landing fees for Part 135 and 121 users over 12,500 lbs. If you are in the area and hungry for a great burger, served without a "Handling Charge," try nearby KAEG. They have a nice restaurant, open for breakfast and lunch."
Signature being Signature. Not my comment, some guy in February of this year.
Someone else's comment there reminded me that Self-Serve isn't where one might think it is, but the ground controllers will point you right to it, if you need help finding it. It's run by Signature and on their portion of the ramp.
At $0.60 more a gallon for F/S, and both of them having the exact same F/S price, I'd give Jet Center my money. But that's just me. Some operators have "deals" with Signature and/or need the pampering and pretty furniture for passengers to see for five minutes as they walk through to the aircraft.
And I know the OP asked specifically about a KSAF stop, but frankly, I agree with the above guy if you're transient and just needing fuel in that general area of NM... I'll stop at KAEG with its very easy to get into and out of S/S pumps and be on my way. But KSAF is nice as a touristy stop and KAEG really isn't. 45 nm away.