When you say local currency do you mean fiat-money like Dollar or Euro? If so I would say that Steemit has an advantage because the money is created from inflation and therefore requires no investment. I haven't tried Sola yet, but I am testing the Akasha platform and what they offer is a chance to invest in them in Ethereum. The drawback with Steem is that you have to go through a big currency like Bitcoin or Ethereum to cash out, but the dream here is that you will be able to actually by things directly with Steem - that is actually the dream with all the crypto-currencies and here Steem has the advantage that it has no fees... But I will definitely try the other networks too when I find the time - I just looked at Sola today and it is next in line...