Fuel Injection add on??

I have a 340 that is pretty mild ( putting out around 375hp). I currently have a holley with vacuum secondaries on it and I am considering switching to an aftermarket throttle body injection system, such as the fast fuel or the MSD atomic system. The main reason I am doing the is to improve the driveability of the car.I am just curious if anybody has made the switch and which system is the best. Currently I am leaning toward the MSD because I already have a MSD 6AL ignition box and if I switch from the electronic distributor to a small cap HEI distributor the Atomic system will also monitor and adjust the timing. Is this the best way to go or should I just go with like the FAST system that is also self tuning but doesn't adjust the timing??

Any ideas will be helpful, pretty expensive upgrade and I only want to do it once and wish I had gone a different way