But that's not what investors want to hear, is it?
This makes me wonder: who really are your competitors? The ones that really might kill you?
edit: for the more pragmatic, add "Be grateful to your competitors and then have them crushed."
If your competitive advantage is that you have the best UI, that isn't good enough, because that can be copied. What sets you apart which your competitors can't replicate, or which puts up barriers (assuming you have some market share).
Those are my thoughts.
Jason Fried has said that "the copier doesn't know why the original looks the way it looks.", therefore superficial imitation is insufficient.
Look at the way you approach a problem, can you hit two birds with the one stone. What about 3?
Its an important decision.