I'm new to distributor tech, so be detailed please.

If this has been posted before just link me to it, and I'll be thankful. My searches only showed me threads on the electric boxs and not comparisons of the two types.

My question is what are the reasons to ditch your basic HEI distributor in favor of getting a electric box such as MSD 6 series. I am only interested in three functions from my distributor unless I should be aware of others:

1) Reliability (obviously)
2) Power increase (HP/TQ if this is possible)
3) Ease of use/Flexability (must be flexible yet not confusing)

I have a sbc 355 pushing just shy of 500 tq. I have plans for a blower (roots style) in the next year or three. I want this box to be able to help me run that blower. I don't want to mess with something that's working just fine unless I'm missing out on an important upgrade that will actually HELP me, not just give me a fancy box that doesn't improve anything.