I am at the end of my tether with him! He is a five year old rescue dog, absolutely no recall whatsoever, quite timid, and very, very fast.
He used to have a Rogz H Harness which was fine, lasted 3 years then the buckle broke so I replaced it with an identical Rogz one, but found the webbing was a bit stiffer - I don't know if he finds/found it uncomfortable, didn't seem to mind it. But, he learnt to twist around and back out of the harness altogether...I think he realised he could do it because my husband tends to walk and let the dogs follow, dragging/pulling on the lead if necessary because he prefers to walk fast. I always make sure both dogs are in front, so I can keep an eye on them and don't mind dawdling while they sniff!
He seems to have hypermobile joints and can twist his legs right around, so the harness is tight enough for walking without it slipping/gaping, but he still gets it off....