Lane Anderson posted:x2 for Rancho. Theirs are the best in my book.
Rancho is where I would send almost anybody. They are perfectly adequate. I've had them build 4 transaxles for me.
But the "best" is such a big statement. They're by far the best value, and have the largest selection of used OG gears out there. But for absolute, spare-no-expenses, all new parts quality, I'm not sure about that. Clyde Berg seems to be a name that comes up a lot in conversations, and I'm sure there are guys even more anal. It's possible to spend a fortune on a transaxle-- single gears can cost >$300 from Erco or Weddle.
I had Justin at Blackline Racing do my last couple boxes, and felt like I got a level of custom care and concern I didn't necessarily see with my last Rancho-built box, as it should have been for the price. Still, at the end of the day, I wouldn't call Blackline "the best". @DannyP did his own-- I wish I had the time, inclination, and fixtures to get something like that done. I can guarantee that he cared more than a guy standing at a workstation in California.
It's probably just semantics. I'd have Rancho build another box. I'd just know it was a good value- not necessarily "the best".