I can agree that carb tuning is definitely one of the limiting factors that had me considering EFI a little harder. I originally did a carb swap to cut costs on my build because I just wanted to drive it, but I never did get the carb dialed in. I bought several jets and springs trying to get things right and was never very happy with it. I know with more time I could have gotten there, but nickel and dime-ing tuning parts was starting to add up and my EFI system fell into my lap. I got an MS setup used with pretty much everything I needed for $700 including several parts I didn't need (like a smallblock Mopar EFI intake) that I sold off to bring my system cost down closer to $300-400. Granted I had to take a chance on used parts and do some troubleshooting and rework to make the harness I got work, but in the end it's been fun for me because I like tinkering with things.
The openess of the MS system was a big draw for me. You can pretty much make it do whatever you want it to do, but it will add up over time. The nice part is you don't have to pay for everything up front. You can add things like nitrous or boost control later, you don't have to work them in from the beginning. For instance, I worked on a project in college that used an AEM universal ECU. The ECU alone cost $1500, plus $900 or something stupid like that for a blank wiring harness, but it could pretty much do about whatever you wanted. I've found the MS system can be made to do all the same things, but it's more of a modular setup. You can buy a base ECU that'll do fuel and spark only, then add transmission control, boost control, traction control, etc. over time as you see fit. I'm not sure the Delphi system is near as expandable in the long run, but if you don't need those features to begin with then the playing field levels quite a bit.