It's very transparent to use (fees, etc), and offers great 'Multi-Manager' funds to lower your risk if you're not a seasoned investor. These funds more often than not perform well and are managed efficiently. This is a great platform for those who know something about investing, but have little time to give to it.
I think the user experience could be better. I would like to see short pop-up descriptions next to the more complicated breakdowns of yields, etc. Perhaps a bit more basic 'multi-manager' like options would be helpful too for the unseasoned investor.