I don't know about the Juicys as they're hydraulic, but I can say with Avid mech discs the brake levers can make a huge difference. I used LX with the shortest possible pull -I was initially unimpressed with the disc brake modulation. However, using the Avid 2.0Ls dialed down to the shortest pull have made a huge difference to me, and I find the Avid mechs have really nice modulation now.
Given a choice between my Avid mech discs/levers and v-brake koolstops with LX levers, I'd go with the Avid mechs for modulation any day. Admittedly haven't tried the v-brakes with the Avid levers yet though (too lazy and since they're my first choice for brakes, I don't want to take them off!).
Just remembered: I changed my touring bike to trekking bars, so it meant -since I had Avid road discs on -I had to find some new brake levers as all I had were long pull v-brake type levers. I tried the dual purpose Tektro (can't remember the model, but they are supposed to be for cantis or v-brakes) levers but even on the canti setting, the braking was awful..... it was definitely digital braking! It felt really hard once the brake lever was pulled. I was very fortunate, I found some really old mtb canti brake levers with very low cable pull, and the brakes are wonderful once more. Anyway, here's a vote for Avid mechs -with good levers.