QUOTE (Midas @ Oct 19 2012, 01:10 PM)

Yes, but there is no reason they cannot specialize (especially when they are starting out). Also, if the fixer is the source of all things, why do runners need that street doc, gun runner or warez contacts if they can just ask their fixer for it?
Usually, you want it because the Fixer will charge you a finder's fee - that, or the Fixer doesn't actually interact with that person on your behalf, he
sells you the contact for a large upfront fee.
Also, if you take your contact yourself, you have it, and can work them as a contact - getting perks thereof, potentially, if you get their Loyalty up high. With deals through a Fixer, it's business as usual.
For example: after the first run in my game, the group face/hacker wanted to upgrade the implanted rating 4 commercial commlink in her head with a Rating 7 Milspec commlink they stole. None of the group was a cybersurgeon, and none of the group had a cybersurgeon contact, and they didn't want to trust the job to a patch-you-up street sawbones. Nor could they go through the usual route of getting some false IDs and taking her to a commercial bodymods shop, because the ware in her body is all Beta-grade and black - no serial numbers or anything.
They paid their Fixer to arrange the deal, and the character (and the character who went with her) were picked up at their Fixer's warehouse by a black car with tinted windows, prevented from seeing where they were going, and driven to an off-the-grid Shadows clinic somewhere. The job was done professionally and quickly (just an outpatient procedure to change the guts of an implanted commlink, really,) and after being briefly lectured on the unusuality of her hardware (and being given the name of someone in New York who might be knowledgeable about such things, if they wanted to pursue it,) they were taken back the same way.
Quick, clean, professional - exactly what was paid for, and little more besides a story hook they didn't bite on.
QUOTE
At the high end (the sort of fixers the PCs might have) will probably be established and have that large network of contacts, strings that can be pulled and favours that can be called in as you say, but all these things are not strictly necessary.
Fixers can come in all shapes and sizes, and there is room in the SRverse for small-timers as well as the movers and shakers ...
In the small-time, anyone with some good local Contacts can be a Fixer, and a small-timer might be
more useful to you than a big mover/shaker, depending on what you need.
Need to get guns in Seattle? Any Fixer can do it, or you can do it yourself by calling up your friendly local gun-runner or Ancients lieutenant.
Need to get a sniper rifle into position in the empty corner apartment on the 19th floor of the Hylonome building, a job complicated by the fact that they have a security force made up of unemployed Lone Star officers carrying better gear than they had when working for the Star? A big timer can do it, but he'll do it expensively, by arranging to have a small-timer Shadowrun to do it. A local, small-timer Fixer knows the guy who does the building maintenance, and pays him a reasonable fee to just take the gun into the apartment and leave it under the bed.
In the overall, a mover/shaker is someone you'll get more use out of, but it might be worth taking a small-timer with lots of local contacts if you do a lot of work in, or live in, an area.