I've a 456 Summer Season, it's got the On-One smoothie light headset which seems fine (but it should as it's fairly new). I've also got some Hayes Stroker Rydes on a different bike, they're ok but mine feel wooden and not too powerful, I think it might just be the pads though, as my mate's ones are much better feeling. My gf's juicy fives feel much better to be honest, I've not rode the threes though.
If it's a first mtb then I'd build it with what you've already got, any hydro brake will be likely to be a significant improvement on bikes she's ridden before.
I've a 456 Summer Season, it's got the On-One smoothie light headset which seems fine (but it should as it's fairly new). I've also got some Hayes Stroker Rydes on a different bike, they're ok but mine feel wooden and not too powerful, I think it might just be the pads though, as my mate's ones are much better feeling. My gf's juicy fives feel much better to be honest, I've not rode the threes though.
If it's a first mtb then I'd build it with what you've already got, any hydro brake will be likely to be a significant improvement on bikes she's ridden before.