The advantages of .45acp over .44 spl are two as I see it. First practice ammunition is a whole lot more common and as a result less expensive. Second the ammunition commonality with the model 1911-A1's means that if you are with someone with such a firearm you could in a desperate situation share ammunition. The second is an admittedly minor consideration but the first is often a big consideration. I have heard that Charter is going to come out with a version of their bulldog and bulldog pug in .45acp.
Their goal is to tap the market for the less expensive .45acp ammunition.
The advantages of .45acp over .44 spl are two as I see it. First practice ammunition is a whole lot more common and as a result less expensive. Maybe,but anybody who is serious about shooting needs to reload,and not all autoloaders feed wadcutters real well. This isn't a problem with a revolver,and a wadcutter is a MUCH more effective bullet than the RN acp load. Yeah,I know about hollowpoints,but my theory is start with a big enough bullet,and then put it where you want it.