I've never used the Summit version of the carb but have used the Holley version a while ago and it was a fine carb once tuned. I don't think you can go wrong with either carb. All things nearly equal I'd go with the Holley branded carb - you'll have an easier time finding local guys that know them and how to tune them as they're used for racing in nearly every class.
That said - since your ultimate goal is to do an EFI setup I would just rebuild your edelbrock carb - about $40 worth of parts and you'll be like new again (new floats, float needles, and a top gasket and base gasket) - pull the carb, clean it up real good, set the float levels and run it until you can afford an efi setup. There is nothing wrong with the edelbrock carb that you have once you get it back to running good and that's what I'd do instead of spending a bunch of cash on a carb you're only going to temporarily run. If you want electric choke I'm fairly certain that they sell an electronic choke conversion kit for it for about $50-60 - which might be worthwhile if you're going to run it for a year or so - even with that and the parts to refresh the carb you're under $100 for everything. I wouldn't go with a "tuned" carb from anyone if the thought is to get rid of it anytime in the near future as they cost more and depreciate a little faster than a std. holley carb (at least from what I've seen)
Just remember with a Holley you'll have to figure on getting the fuel lines / fittings to hook it all up so that will be a little bit of money in addition to the carb itself.
1968 Mustang Convertible - Built 306/C4/8", disc brakes.
1966 Mustang Coupe - building for daughter... 5.0 EFI / AOD / narrowed 8.8 / 4-wheel disc / Integrated P/S... project creep anyone?
1990 Mustang NCAA/7-up Convertible