OBi 100 only has a REN of 3. If it had a REN of 5 like Linksys PAP2T (on each port!), I'd be comfortable with lowering the REN for the sake of PoE, but if it came down to PoE vs. REN > 1, I'd have to prefer REN > 1.
And yes, I have already invested in PoE switches, so I'm clearly a PoE fan, but it's not my #1 priority.