The tier one has the same amount of stam, two sockets for more stam, more armor, and more avoidance. You lose a little bit of threat from the hit rating, but even that is partially mitigated by the extra strength. Go with the tier.
If you're not having major threat issues, go with the previous poster's advice. If you need the threat from hit, I would still use a hit/stam gem to activate the bonus instead of pure hit though. For a tank, every gem should be either pure stam or part stam even if you're going after socket bonuses.