The Avenger is definitely a BMX Cruiser...and that seems to be what the Sully is shooting for as well.
There was an Avenger for sale locally for almost a couple years...near mint condition...for $550 towards the end (I think he gave up). I was tempted, but, it is a mild steel frame except for the cr-mo downtube. WTP is a real quality bike company, so I don't no why they cheaped out on the Avenger. If you run across a used WTP Champ...that is a nice full 4130 3-bar 26" bike. The Avenger will have much better components than the Sully, which is really just a dept. store quality bike.
Cap...I have a Framed Twenty9er. Well made frame...crap components.
If an Avenger came up locally for a decent price, I'd snag one as they are a sharp looking bike. But...price would have to be 'good'.