Strike Commander is my default in teams because the radar jammer and combat regeneration make it more forgiving to use near the front, and the extra bit of speed helps it keep up when expanding. You don't really see how many comm snipe attempts you avoid by not showing up on radar, but I think it's fairly substantial.
Recon Commander, I pick almost entirely to streamline openings. I tend to use my Commander as a slightly mobile Caretaker later, and the jump doesn't contribute to that but the low build power detracts from it. But a strong tempo start from a jump plop, or even the modest eco bonus from taking an otherwise inaccessible metal spot in the first minute, can more than make up for its lack of build power.
Engineer Commander is the baseline for when I don't intend to put my Commander on the line at all, which is rare. It's also comparatively strong in 1v1 or small teams where I might be doing a more intensive eco build-out but the base-metal-to-player ratio is higher.
Guardian Commander is niche in my playstyle; its friendly greeting drone does the opposite of Strike Commander's stealth, so I only use it if it's going to be underwater or very much in the opponents' faces, and the latter usually requires a morph.
