I’ll chuck a ‘from first-person experience’ +1 in for BIRD.
Lifetime, transferrable frame warranty (though, to date I don’t know of anyone that’s actually had to use this), direct contact with the guys that own and run the place and, to date, a 100% positive turnaround and resolution on any repairs or warranty issues I’ve had in 14 months ownership.
It’s worth mentioning that all the issues I’ve had have related to standard, third party components – i.e. stuff that can and does happen with any bike. It’s not BIRD’s fault my Reverb developed a leaky lever, but they sorted me out with a replacement, no quibbles.
It wasn’t BIRD’s fault that I ham-fistedly snapped the lever on my Maxle Ultimate two days before an event, but they sold me a replacement (at well less than RRP), posted it the same day and had it on my doorstep within 24 hours.
It’s also not BIRD’s fault my Monarch’s developed a clunky action, but Dan (one of BIRD’s founders no less) still hooked me up with a returns form, direct to SRAM to cut down on delivery & faff time to get it looked at.
They really are quite excellent to deal with. I can only begin to imagine what my experience might’ve been like had I had to go through someone like Canyon for help on this stuff… Traumatic, no doubt.