Ive only done one trial shirt, but from the experience and final product I'll be ordering more.
I measured two good fitting shirts (and averaged them). I followed the instructions on their website on measuring and all went really well. Turn around was probably 3-4 week until i received the shirt. But i imagine this would be very dependant on time of the year and their workload.
Ill be making one small change to a measurement, and detail then order some more shirts. Then the next part will be some trousers (which I'm probably a little more apprehensive about).
You can also send in a shirt for replication. But I haven't had experience with this.