Modo seems to have a very fast development progress. When its features are finally completed (ie, character animation), I could see in the distance that everyone will want to have it. Let's just face it, this is the most modern 3d package around that doesn't have that baggage older ones have such as UI/workflow issues. The creators knew exactly what those issues were when they left Newtek. I won't be surprised if one of these days the same thing will happen with XSI.
Modo is definitely a must have 3d product. Of course, we could still be loyal to our respective favorite apps. (I will be.) But I no longer see the point of spending a year or two learning one of the industry standards when Modo is fast becoming the leader. Kind of like Photoshop literacy is a must.