I wasn't really sure, so I checked Waypoint. I guess SWAT counts as Slayer type? I didn't see a separate tab for it.
Anyway, I'm at about .85 K/D for slayer, where I spend most of my time. I mostly swap between big team slayer games and swat games. I throw in some flood and CTF when I want something different. Funnily enough, I'm .94 in CTF, though.
I like CTF, but aren't usually the flag carrier. Whenever I'm at about the flag, or I've just killed 2 people who were defending it, someone else grabs it, so I'm on escort duty. Which is fun, but I think that's why my K/D goes up there, since I'm not capping much. I float between escort and flag defense.
Anyway, yeah, .85 Slayer. And most of that has to be SWAT, because I see my "favorite weapons" the top 3 there are BR, DMR, and magnum. Though, I appear better with the pistol.
K/D by weapon:
BR - 0 DMR - -67 Mag - +16
I might just go pistol more often haha. Definitely going to stop using the DMR, though.
edit: I looked further down; my highest K/D is +17 with plasma grenades, haha. "Sticky" was always my favorite medal in the older Halos. Looks like that hasn't changed, if only slightly better than pistols.