Baby bear! Looka them new duds! Wow those're shiny! Why what's that?! You have four whole pieces to tier 10! Guess what you got?!
Episode 4-I mean 10: A New Cooldown
The 4 piece tier 10 bonus is amazing. It takes one of your abilities, Enrage, and turns it from a double-edged sword into a shiny light from parted clouds and something you want for both offensive and defensive purposes.
Enrage has a base effect of giving you rage at the cost of reduced armor for as long as the effect is active. Once you put on that last piece of tier 10, though, all of a sudden... you get rage! You get reduced damage! You get a NEW CAR! Wait, no, scratch that car bit. But the rest is true.
Once you have 4t10, Enrage gets a lot more useful. I don't have 4t10 yet, but when I do, I'm pretty sure I'm gonna start every pull with it and probably blow it in conjunction with Barkskin and sometimes I will get enraged when I'm sitting on my bench in the north bank. Essentially, since it's a relatively short cooldown at a minute, it's worth blowing it every chance you get.
If you don't have 4t10, then here's how I get around the reduced armor: I hit enrage, and then wait 8 of the 10 seconds the effect is active. The extra 2 seconds give me a chance to get in and do the pull and start the fight while I still have all the rage I'm gonna get, and with all the armor returned from the effect falling off just before I get punched in the face. Small thing, but I like details.