In reply to Richardhobbs:
Flys (Flies?) are pretty heavy; the old ones even more so. If you can find a deal on some second hand Quarks, on the other hand, go for it. Lightweight, modular, great for general mountaineering, zooming up grade II gullies, or harder things, should you get the urge. And if you do want a bit more heft in the head for climbing ice, the pick weights work well.