As some have already said, there are advantages to both, and it boils down to what you personally prefer. I have a 2 piece Griffin that is a great bow, and of course the Shrews are very similar. They make great 2 piece bows. But when it comes to air travel, I actually think a 3 piece travels a bit easier. My Griffin is 64", so when broken down is still more than 30" long. A three piece breaks down to be more compact.
If you can get a chance to attend Kalamazoo, that would be well worth the effort. Lots of great bows there and you will be able to see and shoot them all. If you do, make sure to stop by and check out the RER 3 piece LX. There will be plenty of others to try as well.