I have had both and clearly the Carter (Edelbrock) is easier to obtain parts for and it fine tuneable which is often necessary due to the ethanol fuel available today. The Rochester sometimes can often offer a smoother idle .
I personally would locate a used Carter AFB from a 62 to 65 Cadillac and rebuild it. The Edelbrock is fine but you have to adapt the TV rod plate if you running the earlier Jetaway Trans and your stock airfilter will not fit without modifications . Cost wise you can buy a used correct AFB and rebuild it for much less than the price of the Edelbrock
I just rebuilt an AFB for my '65 Riviera and comparing it to the Rochester 4GC that is on my '64 Eldo (and was on my '63 Riviera) I'd opt for finding a used Carter AFB and rebuilding it. IF you were willing to change to a '67 429 manifold and fit a later Rochester Quadrajet, that'd probably be better than the current Rochester, but then the stock air filter would not fit and you'd probably have to modify linkage. The AFB is a good carb - just make sure to source the aluminum gasket shim plate to keep the exhaust crossover gases from corroding the aluminum AFB base.
I have run both on my '61 CDV and '64 CDV and prefer the Edelbrock to be honest as it is easier to tune and seems to give a bit more performance and fuel economy. I had a Rochester 4bbl professionally rebuilt less than a year ago and it lasted on my motor about 6 months before the ethanol became an issue and gas started flooding out of everywhere. Mind you I drive my cars at least a day a week so I do not think ethanol breakdown was an issue but who knows? Plus the Edelbrock looks really pretty with a chrome air cleaner and Offy valve covers but I suppose I am not the "it's gotta be absolutely stock or it's rubbish" kind of guy. Either way, both your choices are quality made American products and do justice to these wonderful cars! Don't be afraid to tinker, this hobby is all about what YOU want!
I figured the needle and seat got wiped out when I saw all of that 93 octane gas coming out the top of the carb like a volcano. I can try to find the Viton ones to replace what got destroyed since I paid good money to have the carb overhauled and it didn't even last a year. Lesson learned-if you have the time and money, do it yourself. Normally that is the case with me but I wanted the carb hot tanked since the car had not been driven since 1979 but I sort of regret my decision now as I have to "unfix" it.
I wish I would have read this two years ago when I searched, searched and searched some more for a pesky vacuum leak on my '61 CDV 390! Lo and behold, there is a hole in the underside of the intake for the choke tube that absolutely NOBODY ever knew about at car shows, "old timers" get togethers, etc. Of course, none of 'em ever had a Cad so their talk about flatheads, 409's, SBC and the like was interesting but left me scratching my head. I have been working on Corvairs for 30 years but that was of no help at all. Good to know of all the experience in the world of Cadillac and yes, after plugging that hole, putting an Edlebrock carb and TH400 trans and delicious Offy aluminum finned valve covers on the '61, she runs better than she did new...I hope.