I'm looking to play with stunt kites as well as foils. I was looking at the Prism kites, and the Micron seems like a bad-a$$ little kite.

However, I was wondering, what's the learning curve like on this thing? Anyone have any feedback or tips?

The Micron is probably no the best to learn on . Fun kite to fly but VERY twitchy and FAST!!!! Don't let the size fool you, it is tiny but considered a kite for skilled intermediate to advanced pilots. Going from a foil to a Micron is like going from a Greyhound bus to a Ferrari F1. Instead of the Micron,, I would suggest the Quantum for learning. Even though the Quantum is one of the larger kites, it will still fly faster than your foils and be much more sensitive to input. The Quantum would be more forgiving than the Micron and easier to learn on - plus it will have a much more solid feel and a little pull which will make it easier to learn.

What about a Nexus? The quantum is a little expensive for my budget range...

The Nexus is a fine kite to learn on. It is a bit smaller than the Quantum so it is a little bit more sensitive to input but holds the same Prism quality and is a great kite. The Quantum is much more forgiving when you screw up and it does fly a bit more controllable and smoother. If you can spring the extra cash, get the Quantum. If not then the Nexus would be a great alternative.

Kent is right on on what he is saying. You won't go wrong with his suggestions.

i second (or is it third) that you don't want to buy a micron right off the bat. Buy a Nexus or a Quantum, go up to the E2/E3 then a Micron. It might be counter-intuitive because of the size difference, but as far as tricking and precision flying the Nexus and Quantum are the most forgiving. I have all of them and absolutely love them when I am not flying my powerkites. It also requires less space to fly and is cheaper. Of the 20 or so stunters I own combined, aside from the Fearless and Rev's, the cost of two of my power kites is more expensive.
Plus, you would be surprised how many powerkite folks congregate around me when we have no wind and are in a blizzard and I am still flying, albeit a no-to-low wind Prism 3D.

For stunt kites try www.gwtwforum.com