If your format is heavily tilted towards 2-colour decks (like mine), they're an easy include; if your deck is 65% black and 35% red, you can still get out Nightveil Specter T3 a majority of the time if you drafted your lands correctly. Same goes for Boros Reckoner in a deck that's mostly white or mostly red. In that regard, I consider them more or less monocolor+, meaning they'll fit in a good percentage of decks, not just the ones composed of their particular guild. From that lens, I view Boros Reckoner as a reward piece for mostly-white or mostly-red decks, and it has some sweet combo potential with red wraths and ping effects. On the other hand, I had Nightveil Specter in for a while, but it was real boring. Boros Reckoner is powerful and exciting enough to do work, though.
Re: cards with battalion; the ability proved extremely difficult to trigger in my environ in the past with any consistency, but if you're going to try it, Firemane Avenger is about the only card worth trying it with.