There is only one different coin which is Ethereum. So real question is, do you want invest in Bitcoin and Ethereum and you understand that Bitcoin hold value and Ethereum not because it have whole different design?
There are plenty of fundamentally different coins, but putting money in on the basis of their technical merit is pointless. No one cares. There are coins that have been 51% attacked, rolled back, hacked, and they're all still chugging.
The only thing you need to understand is which one will grab the most hype and lets you get out in time and no one knows anything about that either. To 97% or more of people all of these coins are nothing more than three letters attached to number on an exchange that goes up or down.