I currently run a 383 stroker with an Edelbrock 500 cfm carb (manual choke), Edelbrock performer intake, camel-hump 2.02 heads, headers, not sure about the cam, but it seems a bit lumpy and as far as tranny goes, I'm currently switching to a built up 200-4R that can handle up to 550hp, way more than I currently have.
This is a street driver that is built for fun, but may see some strip if I get my greasy hands on a trailer.
I've recently picked up a 750cfm performer series Edelbrock carb (with choke).

I don't really have any complaints with the old carb, but which is the better one? What do I stand to gain/lose if I put on the 750cfm?
(My engine will probably be on the stand for another month as I am still de-greasing the sub frame)

The 500 will probably give better low end throttle response, but the 750 will definately let it breath better above 5,000 rpm's. I think you'll be very happy with the 750. It's what most carb makers recommend for a 383.

Go with the 750. It might be a little less responsive on the low end, but you should see a HUGE increase with the bigger carb on the top end.