I like Elmax slightly better than s30v. I like M390 quite a lot better than either of them.
Elmax sharpens up "better" (meaning a more screamingly sharp edge) than s30v for me, and holds it's working edge about the same. I also find it easier to touch up than s30v.
I actually like ZDP better than anything else for "surgically sharp" small knives (the Dragonfly in ZDP is fantastic for this), but I find I have trouble keeping them "working sharp" for general purpose use, and re-sharpening them when they dull is harder for me.
For a small precise knife, my favorite of the steels you listed is ZDP. For a general purpose knife, my favorite is m390.