You will probably get a strong argument on both sides of this question. A lot of people will swear by the original SU's, but I think going to a Weber makes a lot of practical sense. Webers are a common product, and well known to parts supliers and mechanics. They are very reliable and can be ignored for years. SU's are exotic items, found only in Volvos and some classic British cars.
There are more than one Weber carburetor to choose from. The standard DGV two barrel, DGEV, the same but with electric choke, there is even a high performance dual carb set up using dual DCOE's (big bucks). I recommend the manual choke models, I like to have control of what the choke is doing. For what it will cost to have your SU's rebuilt I think you can buy a whole brand new Weber set up.
Tom