A B20 in that vintage of car is definitely a hot rod setup. Weber is a decent carb, but unnecessarily complex compared to the rock-solid SU. Many consider a weber an upgrade, but you'll find a lot of people saying that they are not really a performance carb and not especially economical. Still, it's a popular bolt-on fix, for "problem" SUs/people who have "problems" with SUs.

Whether you want to switch back to SUs really depends on what you want the car to do. I like the SUs myself, they are really simple and not too hard to learn to tune and rebuild. Parts can be a bit pricey. If you want to switch back you'll need to find an intake manifold and probably a pair of HS6s. With a B20, you could go with HIF6s, but probably more complex than you need. IMHO, there's not as much support/parts available for HIF6s.

Still, sounds like a nicely upgraded setup. You probably don't need to change anything. Congrats on the purchase!