I'd rank them in this order from most useful all around to least useful all around, 10, 7, 9 , 5 & 2.
10 - I like the overall length of the 10/2, but the 10 is a lot thinner and lighter. I love the 10 and I always have one close by.
7 - very fast in the hand and a very good overall utility knife, a bit long for most cutting and a bit short for really good chopping
9 - I have carved a fork with it but not my first choice unless chopping, great knife though
5 - don't like it, looks cool but other than for knifefighting (which I rarely do anymore) I think other blades are better, if it was a rope cutting competition I'd want the 5.
2 - heavy in the hand and on the belt, I have 2 of these and they are mostly for loaners to folks who might break one of my other blades. Otherwise not a big fan.
Not a knife expert, I have at least owned and used all of them and I think I just did give away my last 5 recently.