What the last guy said. That or make sure you make good friends with a local Mechanic. Buying is not really an issue in terms of operations and maintenence. At least if you have access to a good mechanic who is not what I'd call a serial rapist.
On the other issue, which is actually a true conundrum for many, BUY or BUILD, you have to seriously do the math and the home work. And be totally honest with yourself.
There are Serial Builders. Those insane individuals who will build 3 to 10 aircraft in their lifetime and spend almost no time on the stick before selling it and starting a new project. They think life is over if they are not drilling holes or driving rivets.
There are builders/flyers. Guys who only build because they want to FLY and its a means to get an amazing aircraft for far less than a factory pig with a half the performance. This describes a lot of builders and also explains the various levels of quality/finishes you see, all based on how desperate they are to fly versus how much they enjoy the building process. lol.
Then there are FLYERS, who hate the entire thought of building because frankly, its all about the FLYING. Building to them can be a miserable enslavement because every day in the basement is a day NOT flying. To them its a necessary evil because the end result is this amazing, astounding, knock-your-socks off tiny little fighter plane that you just can't order up from Cessna. If you are one of these guys, keep thinking 13,000 RIVETS, 13,000 RIVETS...and you may become a BUYER pretty quick. HA.
The question you need to answer to yourself is, Which are you? Are you somewhere in between? You gotta really think about that.
So, having thought about it, do some math.
Example: On Vans calculator, if you keep the aircraft simple, you can build an RV-8 for $75,000 to $90,000. This does not take into account, time, family, location, ad nauseum. Nor does it take into account todays builders trends to turn their sports planes into mini-airliners with $30,000 worth of flat panels and auto-pilots. BUT, if you keep it simple, yep, you can build an 8 for under 90 Grand. Factor in the years it takes to build.
Now...surf Barnstormers or Trade-a-plane. Hmmm...you can, and quite often, find a perfectly good RV-8 for $75,000 to $90,000 IF you want it simple and with out all the televisions on the panel. Add gimicks and gadgets and it quickly soars to $120,000, but an analog RV-8 can be had for about the same price as it takes to build, but without the years invested in driving rivets.
And there is the rub. Buy? Build? And why you need to decide your goal. Learning experience of the built, to fly a mini-fighter, or both?
Looked at that one way, it seems Simple. BUY. Why spend 2 to 5 years of your life, risking your marriage and thumbs, when, if in the end, the money spent is about the same?
Well...building means YOU control the QUALITY. You know exactly HOW it was built, so if you are skilled and careful, you get a safe aircraft by doing it RIGHT yourself. Every time you pull 4 G in a loop you know you did it right and the wing will stay with you.
Does that mean a bought airplane is a risk? NO! It means IF you are going to buy one, you do a lot of homework on it first. Consider who built it. What is their background? Whats the plane look like? I do not mean paint. Look at the details. Smokey rivets? Missing rivets? Out of trim flying surfaces? Owner making excuses for issues? You can tell a fair amount by simply looking that thing over before committing.
No one can give you a complete and definitive answer, but you do NOT have to build to get a really amazing RV-8. Cost wise, especailly in this market, it may be a wash either way. Prices are down. Its a buyers market. If you happen to find an plane for sale that was built by a Naval Aircraft Mechanic, who, after retiring, worked as an A&P for 30 years, then its probably a safe bet! lol. And even if not, some of the builders out there today are amazing in how detail oriented they are. So buying is perfectly viable now days. All you gotta do is keep your end of the bargain and make sure what you are buying is worthy of the money.
And if you are not sure, find one of those insane Serial Builders! By the fourth time, they about got it right! HA.