The issue is not with opening, but rather with how the knife closes. All axis lock owners know that a well adjusted pivot comes open like an assisted knife. The way the axis bar rubs the smooth tang makes for a silky, fast and easy opening. The assist basically makes a knife open louder but not faster or better. I feel that closing an assisted knife is much more difficult. The assist spring must be overcome when closing. This takes two hands or a hand and a leg... something to force the blade shut. The closing issue is the only thing I dislike about assist.
Some knives close about half way or more before the spring starts to compress. These are ok because the blade is easily in reach of a finger and can be closed one handed just fine. FYI, the 580 and 581 are NOT this type of knife. My father has them, I've played with them a lot. AWESOME knives for sure, they just don't close right. Edited to add: Dad carries a 550 Grip most of the time. He has bad arthritis and the 550 is easier for him to one had. The stroke makes one hand a must and the arthritis adds to the what knife dilemma. For a guy with only one bad hand the Axis is King! No liners, frames, compression, CBB, back, mid or whatever else lock just isn't as easy.
