Anybody use these? They are bit cheaper than an I20. I have had great luck since switching from pgp to 5000s, but I haven't tried the stainless 5004. I have ordered a box of them to try. I have actually had great luck with the stainless I-20, but the 5004ss are a little cheaper and I despise hunter. Is the spring as stiff as an I20? Are they as tough as a Stainless I-20?