It's reasonably fun for a bit, but the interface is kind of clunky. For example, there is no fixed place to submit your word. There's a little green check that moves around depending on the length of your word. If you miss the check, the whole word disappears.
Also, it would be nice if repeat words were dismissed without a popup box. When I'm playing a speed game like this, the fewer popup boxes I have to dismiss the better.
Overall pretty decent, just needs some work on the interface.