If you stay with your car and its just an MOT then fine.
The Autocentre near us is aweful with a string of issues I'd rather not go into as we had to write a report for one customer who used them.
It's all dependant on the quality of staff and these quickly quickly centres just dont have the time to do a job properly, needles to say I don't think this will attract any super star mechanics. All my own personal opinion though