Your question is an important one. My own reasons and thought process are similar to the above posters but they haven't mentioned LSA compliance yet... that was a big one for me. Not that I need it now, I'm quite healthy and plan to stay that way, but I've seen friends get surprised by medical issues that don't impair their ability to fly other than legally.

Another reason that I don't think has been mentioned yet, and that I believe should be considered, is the company making the kits. Are they committed, doing business in a manner that is builder-friendly, and likely to be in it for the long haul?

The longwinded version of my personal reasoning can be found here.