Excellent, thanks for all the replies. I was hoping OA's would happen often enough to justify getting the HBO talent. I'm trying to put together a Beastmaster Ranger who has a bit of an Opportunity Attack focused build...still debating exactly which weapon/build to use but I think it's a tie between a melee Twin Strike/Crit focus Ranger using a Double Scimitar, or a mostly ranged Ranger who uses a Zulaat(poloarm-like double weapon) along with Nimble Strike and the feats that boost Nimble Strikes movement bonus. I was also considering a Daggermaster Rogue multiclass with a pair of Wraithblade daggers(gets to add sneak attack dmg to his crits), but I'm feeling like the double-weapon with HBO would add more flavor and be more fun to play.
The Ranged one looks to be an ideal hit-and-run character concept, with a Pet and beast talents, including Cruel Cut Style and Beast Protector, to make the most of his Dex/Wis stat focus. The Melee one looks to be a very nice burst-damage striker, though his damage would be extremely spiky...exceptionally nice with crits but average dmg when he doesn't crit -- and he seems to be pretty squishy compared to other melee attackers =[
Decisions, decisions...any thoughts/suggestions?