Bill: I like dual points for the following reasons in no particular order of importance:
1) I am a heavy bastard and I know of folks who broke front points. Hence two is better than one for security
2) I find 2 works better is shitty ice and as well as mono in hard ice maybe you just need to kick them in a bit harder but you have a stable platform for your achy calves on steep ice
3) I would definitely go mono for true sport mixed climbing but I have climbed up to M6+ in dual points just fine but I think monos would easier on pure rock. I would probably get a second pair just for mixed if and when I started pursuing it more
4) If you can't decide then get poons that are modular and try both set ups and see how you like it.
Joe: started off on monos and loved them, but switched to duals in the past couple of years for the improved resistance to shear out. the dartwins are really sweet in that the points are far enough apart that they don't fracture ice as badly as other poons
Fernando: as bill said i'm climbing on the dartwins now. Used to climb on monos, but found them crappy in chandeliery stuff and poor ice (like that in your pictures). The sidelock system is awesome, once you get used to it ... frustration can be high at first ... but i can now get them on and off without a problem, and once they're on they are super solid - they feel like they're screwed to your boots.