I seriously thought about the Retroject.
Pros:
Bolt-on(ish)
All the sensors are built in
idle valve is built in
Keeps the classic carb look in the engine bay
Cons:
Price
Won't gain much HP over a normal Weber
Lots of people will tell you to just do a 318 EFI, but you need to source all the parts (manifold, coolant outlet, coolant line), fab/buy an idle adapter, fab a throttle linkage solution, fab/buy a TPS adapter, and/or upgrade the TB (stock is pretty small),
IMHO, I'm not crazy about the 318 EFI manifold looks either.
HP should be about the same as a Weber 38, but have better drivability/cold start/MPG
No matter what solution you choose, you'll still need a fuel pump, ECU, and possibly crank trigger if you want to go distributorless ignition.
Personally, I wasn't concerned about the price tag, but I eventually wanted to do ITBs, so I decided it was best to just spend the money on them instead (Winter project)