The K2 Haven BOA is a comfortable good entry level BOA Boot that can help you progress. Not a bad choice for the 5 to 15 day a year rider.
Flex: Nice forgiving Medium/Soft flex.
Comfort: K2 is pretty good at eliminating pressure points with single BOA boots and K2 knows how to build a boot around a foot.
Heel Hold: K2’s BOA system locks in your heel pretty well. It’s not as good as the double lacing system’s that K2 has but it’s pretty good and close to being excellent.
Adjustability: No adjustability with a single BOA. It just tightens the whole boot. You can’t make the upper different than the lower or vice versa.
Flex Retention: The flex starts out medium soft and over time it doesn’t completely noodle. It holds it’s flex well enough for the life of the boot for this price range.
Response: This is more forgiving than responsive.
Traction: Not great but not bad either.
Shock Absorption: There isn’t much shock absorption here because the boot is trying to give you lots of feel similar to a skate shoe.
On & Off Ease: It’s just like most BOA boots out there. Very easy to get off and not bad to tighten. It doesn’t have the liner lacing on the outside so you have to get inside to undo it but it’s still pretty quick.
This isn’t going to blow you away but you get what you pay for and possibly a little more. If easy in and out is more important than adustability then the Raider might be a good choice.