K2 Thraxis are fine, K2 Holgate are quite stiff too. Just make surre they're the right boot for your foot. If you have a frankenfoot the triple BOA is great. Never had a BOA loosen up on me.
K2 boot quality is a hit or miss. My K2 maysis plus stiching failed, so did this year Holgate. Although never had issue with the Thraxis.