How old is the carb?  Pull the carb, reset the floats and check for trash in the seats.  I had problems with the above issues.  I was about to change out the carb to a Holley and that solved the problem.

I am not a fan on spending money for a new carb if the one you have can be fixed, (Don't ask how I ended up with my Holley). There is very little that can go wrong that can not be fixed by someone that knows what they are doing. Even if you buy a new carb you will need to spend time getting it setup correctly for your car.

I believe there is a bit more you have to look at. When it stalls, and you start it again, does the car belch black smoke when it starts? What kind of cam r u running, why would the rebuilder go with smaller jets? Did he change the jets and rods? Did he change the springs also?

I have had holleys for years and no problems.  I was not aware holleys were available for mine, so I went with the edelbrock; otherwise, I would have put the holley.

I'm with gurtz...sounds like a float issue. Could be some trash in one of the needle/seat assemblies, or it may just have the levels too high.
You say when it dies, it fires right back up, but blows a little black smoke. That's an indication that it is too rich(but you knew that), but, running rich, by itself wouldn't cause it to die at stops...flooding would.
Are you sure the choke is working properly?
Do you have the mechanical fuel pump, or electric? If electric, what kind of pressure does it have?
What spark plugs are you using? If they are too cold of a heat range, it could cause the same problem.
I've never been a big fan of Hollys for street cars, tho I've run many of them in the past. I loved the original Carter AFBs, but the Edelbrock ones?...not so much.
A good Quadrajet puts them all to shame, imho. May not look as kewl, or shiny, but...shiny don't get ya home!

I agree with Joel, I really don't understand whay a good mechanic would tell you to get a different carb, instead of fixing the problem at hand. Of the four I own, one has a Holley, one an Edelbrock, and two Q-jets. they are all good carbs, but I have had the least trouble with the Edelbrock once I had it set-up right. Also, there was a pretty good vacuum leak that caused most of the problems, not the carb. I really think you should dig a little deeper into this, and find the real problem, not just buy a replacement.