Very tough choice, for me. For the last 4 days I have been alternating between my 457 and my CS45. The 457 all day, either working in the gun store or instructing on the range and the CS45 every night when I go on duty in the Magistrates office. Two similar, yet different guns that both excell at different tasks.
Pros - shared by both models - compact size/light weight/accurate/very good triggers and sights/bet your life reliable and look good doing all that.
457 cons - plastic sights/Sharpie marker finish which wears rather quickly.......and badly/WILL RUST without weekly........daily proper maintenance.
CS45 cons - Hogue grip is a little short AND a little bulky (but does a great job mitigating felt recoil)/one less round than the 457/recoil springs are hard to find.......well.......pretty much everything CS45 related is hard to find and a bit expensive when you do find it/leather is VERY difficult to find fora left handed shooter and merely frustrating to look for for a right handed shooter/they dont still make the CS45.
When I find my personal threat level is elevated (working in gun store on the edge of the hood - taking wife 2.0 to the mall at anytime of the day or night) I find I gravitate to the 457........and two spare mags.
When my personal threat level is low (District Court Judge surrounded by LE in the middle of the jail complex, or running to the stop n rob) I prefer the ease of carry and concealment the slightly smaller and slightly lighter CS45 affords me. And I am more accurate with the CS45. But am still working with the 457.
So, I vote that you get both. Because you really do NEED BOTH! Hope this helps!
Best regards, 18DAI
Actually, I mostly carry 3913 variants, but like having one .45 version around. 
