I wasn't aware that Martin makes it. If they do, then it's more than likely a good bow.
Plus... if 3Rivers sells it, it's usually a quality product.
I'd rather it didn't have Bartas name on it if I owned it, simply because I don't approve of his antics, but that isn't the point of this discussion... so I'll get back on track.
At $420, I started comparing it to others. It looks almost identical in form to the Martin Bamboo Viper, but the Viper has bamboo core limbs, and carbon back, plus a nice little accent strip down the middle of the riser. That bow is $670.
So... If I were buying it, I'd have to ask myself if it is worth the $250 savings. Right now, I don't know that answer, as I'm not in the market for a longbow right now. But it is a worthwhile question to ask yourself. I've found about 80% of the time, if I pass on a few upgrades in order to save a bit of money, I'm not happy later. But everyone is different.
Good luck in whatever you decide. I hope you enjoy it completely if you do decide to buy it.
All the best,
Glenn