Since season three began, every garen I have played with/faced has had a really strong k/d, such as 12-1 in the game I just played. Is garen really strong in season three, or has my team just sucked?

sword of the divine/cleaver was a nice facelift for him

His buff was back toward the end of season 2 when they improved his ratios. The new items for season 3 are just very efficient for him. The new black cleaver should be called the armor blender when Garen buys it. Health, cd reduction, and armor shred on physical damage are made for Garen. The new spirit visage is also excellent for garen packing a large amount of MR with more cooldown reduction.

With his itemization improved, Garen is more formidable opponent at all stages of the game.

Oh yeah, SotD active on Garen's Q or E is rather nasty, and the new Atma's builds out of avarice blade which helps Garen build that gold quicker. His build is just very streamlined right now.

he benefited from the massive overhaul for AD caster itemization, a few other champions are also reaping these benefits.

I don't know, I raped with Garen in s2, now I can't do **** with him.

SOTD works with his E?