To clarify on the Strength vs Vit: you'll still want enough Vit for you and your healer(s) to be comfortable in the given fight.

The skill speed baseline varies depending on latency usually, but the commonly accepted range is 390-420. 390 seemingly more common.

For big pulls in dungeons, I personally prefer Vit as I can't trust random DF groups to keep me alive or kill the packs fast enough. I only do big pulls with an ae composition with the dps though.