A friend of mine took over 8 hours to get recovered back from donnington to somerset with the AA because they put him on 4 different trucks to keep their costs down by keep punting him from one onto another that happened to be going vaguely in the right direction even though it meant him waiting as long as a couple of hours for the changeover.
Where as with a local garage you are likely to get taken straight there or given a hire car and yours delivered a couple of days later.
Sometimes thats down to European law. Recovery companies now either have to have tacho fitted and comply with drivers hours etc or operate within a 100km radius of the vehicle base. Most choose to use 100km as its more cost effective. But therefore sometimes they have to swap trucks if they get near the edge of an area. AA have always done this, even before the new laws, thats why its called 'Relay'
Complying with drivers hours means they have to stop for breaks. I know plenty of people who have been towed for 30mins then had to wait while the bloke stops for a 45mins break. cant win really.
The 'myth' about contractor based services being better as they can get to you quicker makes me laugh. So the AA are busy and will make you wait for hours where as the other companies have a garage on every corner with a bloke waiting for your call, just in case? LOL
If the AA/RAC are busy you can bet the agents will be too. and the fact that they are 'local'....... Well AA/RAC use local based patrols, so its the same?
With a Patrol based service (AA/RAC) you are more likely to get fixed at the roadside, (80-85% of the time) with access to more parts and equipment. They turn up in a van not a recovery truck. The downside if you need towing a long distance (Less than 8% of the time) you have to wait for a truck. if its a local-ish tow then the patrol can do it.
HTH