Opinions please- new hemi or 408?

I'm kind of in the same bout as you but I have my slant 6 right now. I want the car to be a lot more reliable and get god gas mileage while cruising and ended up stumbling across a trans/ecu/harness/fuse box/ torque converter/driveshaft out of a 05 Rumblebee for $350 so it gets me most of the things I need for the swap at a very cheap price. So I'm heading in the 5.7L direction mainly because that's the deal I came across and it seems like every Dart I run into at shows has the 318/360 in it and id rather be a little bit different then everyone else. If I had found the same kind of deal on a 408 with the extras I might have gone a different route. But I'm excited to start my build soon.