It is worth noting that being fast is not enough to be a good currency for use with ILP. Speed and low tx cost can make things cheaper with ILP because the connector doesn't need to factor in as much credit risk (note that ILP payments are the same speed regardless of underlying currency; between settlements the connector is just trusting that your payment will go through to them. Faster currencies allow settlement more often, so the connector has a lower risk making the payment cheaper and less likely to halt). However, at least as important as speed, liquidity is needed for a currency to be successful with ILP. No connector would accept Ethancoin, because it's pretty unlikely that the connector will later be able to sell that Ethancoin and make a profit. Further when you factor in the cost of setting up infrastructure to accept new coins, liquidity becomes a pretty high barrier. XRP is pretty uniquely fashioned as the fastest highly liquid currency out there today. Speed is not a pain point for XRP, so even if a coin is a little bit faster than XRP, I highly doubt the marginal value that adds would be enough to compensate for the liquidity gap.
by Ethan MacBrough (https://twitter.com/emacbrough)