I would like to say they are a little underrated. I believe the hcca's are more powerfull, and you can drop some of them down pretty low on the ohm loads. XTR's like the higher loads, and they put out some good power. One of my favorite amps i used to own was my xtr 2150, sounded great and it was powerfull. Id rather run the XTR series more than the hcca's but thats my choice, others will differ im sure.how underrated are these things? are they as good as the hcca series?