In reply to TobyA:
Dunno Toby, I do know most people I know with dual pointed crampons tend to leave them as duals OR monos so if monos are definitely wanted you may as well save some weight and get some specialist ones. I have Rambos (as well as G14 and sabretooths), partially as Freneys are quite flexible for B3 boots and it helps to stiffen them up a little.
I find that some ice is better with duals and some with monos. Monos smash the ice up less and are easier to get in sometimes, but on very hard ice the longer mono point doesn't seem to get as much penetration as I'd like leaving a lot of leaverage on my calves. On slushier ice the monos have a tendency to slip. I'm still not sure which I prefer overall.
On mixed monos feel much more natural IMO and you can rock over and pick out small features for bridging more like rock climbing.