The board does look about the same on each amp, but same board does not mean same amp at all, it is about the components in/on the board. Both Atomic and Sundown are known for being very high quality products with high part quality, however Sundown does have much better CS and you know what you are getting with the amp. Tests have shown that these amps will do at least 3kw+ on less than 12v, I do not know what the Atomics are capable of, probably very close to that. It is a tough decision based on performance of the products, but I would lean towards the Sundown. And when it comes to Customer Service Sundown wins hands down, not to mention you can get a refurb, with a year warranty for $700 and it is an authorized refurb.After that long *** post SUNDOWN FTW!! I am actually thinking about getting 2 of the refurbed 3000's to power my 2 HD3 15's