As a long time DIY’s, I would say that kits are an excellent way to go.
From a sonic standpoint, the end results well end up sounding like a commercially available speaker at several times the price (5X is not unusual.
That difference will drop a bit if you buy kits that include flat packs.
If you can live with the cosmetic results, and the lower resale, DIY is the way to go sonically speaking.
My current (hopefully my last*
) DIY project is a pair of Curt Campbell’s and Jim Holtz’, "Bordeaux" designs. They are semi-open baffle.
They use Aurum Cantus Aero Stricture tweeters, Accuton ceramic mids, and 2 8" woofers per speaker. I have about $3000.00 invested, but the end results are easily comparable to speakers at around $12-$15K.
Full disclosure, These are not mine, I haven’t decided on the finish yet.
Other sources to check:
Troels Graveson - one of the best designers out there, Has many great designs. His high end level designs are pretty special.
CSS
SpeakerHardware.com - Source of several of Curt Campbell and Jim Holtz’ kits and flat packs. This is where I got my Bordeaux flat packs.
Speaker Design Works - Campbell’s and Holtz’ own site. Their new Anthology II are fantastic. Just a small step below my Bordeaux.
Javad Shadzi is a fantastic designer. His Helios CM designs are a extremely good.
*yeah, I've said that before. My previous pair of speakers, the late Jeff Bagby's Kairos and woofer modules were supposed to be my last.