I recently bought a 229R DAK. The trigger pull is 1 lb. lighter on the 226 and 229 models than on the 220 and 239 DAK models. (From what I read on the Sig Forum it is because of different engineering on single stacks and double stacks.) I have been using Beretta D model DAO's for 15 years, and also have exposure to revolvers, SA auto, SA/DA autos and Glocks. I love the DAK for a lot of reasons. It seems to split the difference between my DAO Beretta (which is akin to a smooth S&W DA revolver) and the Glock in terms of trigger travel and weight. It doesn't stack like the Para LDA. If you try to stage the trigger, it reaches a natural set point (doesn't click like an S&W) then only goes back a slight bit before releasing, unlike my Beretta which went quite a bit further back. I picked it up and within very few rounds had the hang of the trigger, and am more accurate with it than my Beretta. I shot 100% on my first qualification with it. My Beretta is retired to home defense.
You may want to go to Sig Forum and ask about the difference between the 220 DA/SA and the DAK.