I have the Darkos and love them. For me it is the perfect compromise between the reliability of traditional lacing on the outside and the instant adjustment and strong hold of the BOA system.
With the laces on the outside you can dial in the tightness you want top and bottom and let the inner BOA fine tune the fit. You can move the inner BOA around so that it wraps your ankle the way you want and it really helps eliminate heel lift. I also love popping the BOA loose while on the lift to give my feet a break which goes a long way in the comfort department when riding a full day.