Hi Sneakers we have literally loads of MS companies here. I would guess many are the same as you as most are international. Off the top of my head the ones I am with are Gap, RetailEyes, TNS,Frontline Focus, PerformanceinPeople, Retail Maxim, GfK,mysteryshopperevaluations.com & OptimumContact.
I do feel envious at you folks complaining about gas (petrol) prices. The UK gallon is I believe slightly bigger than the US one but ours is around £5($10) per gallon.
The pizza one is strange as I can understand them checking you got the big one specified but why does it have to be all cut up and bits folded over.
I am on a UK MS'ing forum. We have much the same problems etc as you do. Stupid tiny details being questioned, long wait for payment of fees when you have bought say a burger meal upfront, websites being down, one which I won't name keeps getting distances wrong ie telling you xyz shop is *** miles from your home town when it is maybe 100 miles. Fees for similar jobs also vary widely.
We have an alert section only on our forum to let others know that say TNS currently have xyz type jobs. It is very useful.
I will post the crossword tip on the thread you mention.
A current problem we have is I live in Glasgow. Now Glasgow airport as you know got hit by Al Quaeda nutters last year. Although being Glaswegians they were tackled and thumped by staff and public. So shopping malls now frown on anyone taking pictures so some of the MS's want a pic of the actual shop. Someone recently got held for 2 hours by security staff because of this.