I think in the N900 environment, you have to make your program stand head and shoulders above the free stuff to make any sales. And quite frankly some of the free stuff, while lacking polish, will be hard to compete with. It's a numbers game and N900/Maemo is lacking. OTOH there is a vacuum for great software and if a dev team puts in the hard yards and polish, there is a chance of a decent payoff. Just don't expect consistent revenue after the first month of launch.