I haven't got hands on the 4.5" version, but the 4.0c Comp is the business. YMMV, but for me it is the most ergonomic pistol I've ever shot. It just feels good in the hand and it's easy to get a good grip. I put the Holosun HS507K x2 on it and that's it - ready to go. I expect its larger cousin will be similarly spectacular. My most recent two pistols have been the Echelon 4.0c Comp and the Walther PDP F-series (3.5") and both are homeruns.