I'm definitely getting more interested in Google's online tools. In addition to the client you link to, they offer
hosting now as a pay service, but you get a certain amount of bandwidth free, and that might be plenty for what the linguist community needs. Of course it's always risky to hitch your wagon to any single provider, but in the intermediate term Google is going to remain a major player, and their commitment to cross-platform support is solid.
Their tools play nice with Python, so if we go that route I think we've made the right high-level choice with the ELTK.