So far the only blades I've tried in my EJ89 have been the Derby's it came with, and Feathers. Although I've been getting DFS and BBS with this combo (EJ + Feather), I've not been without some irritation, especially in the neck area. Last week I broke down and spent a whole $10 bucks on 100 Astra blades on Amazon, figuring if I didn't like them, I'm not out much. Well they arrived on Thursday and I've shaved with this blade twice. My first thought is wow! I can definitely tell they're not quit as sharp, but are smoother than I could have imagined. Two days, and two BBS's, without any irritation, even on my neck! I can't wait to try them in my Slim!