^ Well then, seeing I've done BOTH, multiple times, perhaps I can offer a perspective that's a little more meaningful to you...
MY "new" attitude about it is this:
Really, for most/many people, we're taking about a relatively
small amount of money. What?! We're talking about thousands
of dollars, here, many times.
Let me explain:
So I built my quad Daytons and threw in a nice Crown amp. Cost me about $1600 and 24 hours of work at the end of the day. Nice cabinets, absurd performance for my room. Spent about double of that I would have dropped on a comparably-performing (yeah, give or take, here or there) dual Captivator array with the same amp.
Yep, double. But, so what? And I say that as a guy I can almost guarantee earns less than half of the guys on avs that are my age. Just look at what you end up with, dollar for dollar, either way.
So with DIY I have a $1600 on a sub system I'll likely own for 5+ years. But had I saved up for "x" months, doubled down and gone the Cap route I'd have a known super performer ( I SOLD my single Cap to go DIY, btw) with almost certainly a better built cabinet, and a warranty. Never mind I never cut a piece of wood, drilled a hole, got a drop of glue on the floor, swung a paint brush, or bought a 36" clamp for.
Resale/residual value? No brainer.
The above DIY option doesn't even consider my time
of course, which I seem to value much more than many others here, but that's cool, I like woodworking anyway so it's not a total loss, there.
I have no real other hobbies that require $, so I'm in pretty good shape in that dept. I rarely even hit the bars for a night out anymore so I know that puts me in a bit better shape than some others.
But in the end, again, I think the ID market and advancements in the tech in general have put such awesome performing subs within reach of so many that the line has become more blurred than ever. Yes, you can absolutely wring more performance out of every dollar you spend with DIY...but people have to realize that there's also a LOT of value in going the other way, too.
Tight budget and you know your way around basic woodworking? DIY. Need/want off the charts output/REALLY large room? DIY.
Looking for a great subwoofer or two to put you ahead of 99% of your neighborhood (not AVS, mind you) without doing anything but carrying it in the house? Turnkey.
If you asked me for ONE general answer though- after going both routes numerous times- I could confidently answer turnkey at this point. And that's great for our hobby and the hobbyists, alike.