Btw, I just want to add, I am not sure any of these coins (even vcash or dash) will ever be used mainstream. Right now the most important feature in crypto is scalability. I have not seen any coin that could scale to even a single state using it. So, ultimately, that is currently the bottleneck of crypto is its scalability. Dash does not solve this. Ethereum does not solve this. Vcash does not solve this. Ultimately, these coins can NEVER be used as "digital cash" because doing so would hit the limits of their scalability and they would become unusable Implying that they could be is being dishonest regarding the technology.
The only thing that might solve this is mimblewimble which would probably need to be its own alt-coin or side chain. However, a blockchain based on that would not have some of the more advanced features of bitcoin (like advanced smart contracts). On the other hand, it would be much, much more private than bitcoin.