i used perle cotton and my problems were 2:
1. the needles were a pain in the butt. to get an eye big enough, i had to go with a longer needle. since i finished that project, i have been altered to the availability of shorter, sharp needles (you need sharp points for quilting) but i wasn't able to find them locally at the time. that would have helped significantly. hand quilting with a longer needle is not ideal.
2. my "body memory" or whatever kicked in and it was difficult for me to maintain a larger stitch length. this is a practice issue (as in - practice would have helped a lot!) but the end result was my perle cotton quilting was pretty close to my thread hand quilting. this meant it wasn't any faster, and given the needle thing probably about as long in time as regular ole' handquilting.
it did however really stand out, where often handquilting fades a bit (which is disappointing sometimes for the hours spent you know?)
i will do it again. for sure. but with the above lessons in mind
aileen