If you are going to spend the money go MPFI. Get a system that has a wide band o2 sensor or add on kit if you have no experience tuning EFI engines.
I've used both holley and Edelbrock EFI systems. The Holley had much more capability but has a PC interface. However, the Edelbrock made more power, got better MPG, and idled a lot better. Holley's are known for idle issues.
I prefer both sytems over a carb but neither will give the same results of a modern LS engine with factory style computer.