Test drove Papago on an iPhone 3g with ios4. I have to say that it is not really usable as the map draw rate can be slow at times. Half the time the arrow would be moving on empty ground. It would sometimes hang and skip a few metres and also take a while before recalculating a route after a wrong turn has been made.

Of course POIs on the other hand are the best around.
@romraka
So no UI lagginess whatsoever?
Also, does your tracked position come up to be accurate to your actual position?