Not a Howa warranty experience, but a Legacy Sports International. I had a Citadel Trakr .17 HMR with a bad chamber. Legacy said they'd replace the rifle, but I had to wait over 6 months for the replacement. Legacy will handle any warranty for Howa, and right now they told me they are at the mercy of the ports both in the countries their products ship from and in CA.
I had a buddy who sent his .270 Win 1500 in for warranty because it wouldn't shoot better than 2 MOA. Legacy replaced the rifle, but they replaced it with a short action cartridge because they had no idea when they get a long action back in stock. This upset my buddy as he bought a B&C stock to replace the Hogue. So he couldn't reuse his stock on his warranty replacement, he's fixed income so this was a big deal for him.
Other than warranty, I've been very satisfied with the two Howa rifles in my household. My daughter hunts an Alpine in .308 Win.and I bought a Brownell's barreled action in 6mm Creedmoor. Both rifle have proven to be accurate and reliable.