Bruce sez:
"Buying a homebuilt is cheaper than building one or buying a certificated airplane.
You also get a better airplane than a certificated airplane."
Begging to differ here.
I built two VariEzes for far less than what it would cost to have purchased them. The old adage, "You can have it good, fast, or cheap - pick any two", goes a long way in the world of homebuilts, particularly plans-built airplanes. The offset is that you have to spend time to build. I'd rather spend the time to build (read: "Learn") than the dollars to buy an airplane that was built (the vast majority of the time) by a total stranger.
This leads to my next point.
There is NO guarantee that any homebuilt is "better" than a certificated airplane. On the contrary, I've seen plenty of homebuilts (both plans-built and "kit") that were not deserving of an Airworthiness Certificate. Yes, there are homebuilts that could be positively deemed "better" than a certificated airplane, but this would have to include the ability to show that the airplane was better in all ways (i.e. comparing/evaluating the overall airplane against 14CFR Part 23, for example), and not just "better because it goes faster and costs less to operate".
I've seen homebuilts that were well-done, but that had engines and/or engine installations that were quite unsafe.
Building your own has some definite advantages. You are the "whole enchilada" - you are the quality control officer, the fabricator, the assembler, the tester, etc., and (hopefully) you take great care & patience in doing everything as correct as possible. I've seen these airplanes, where the builders not only build for the cost, but for the education of it all as well.
Assuming that a homebuilt that was constructed by someone else is a good, safe airplane is an unsound assumption, from my experience.
My 2 bits.