I have the EX7 and I do take this with me on many of my trips. The only time I don't is if I have a fear of security in the hotels I am staying at. I paid too much money to leave this laying around. However, one of the reasons I went with this was the 17" screen (not the only reason, but one). It is so much nicer for playing games and watching movies. During the last seven months, I have been on the road for about 10 weeks and getting ready to leave for another five weeks next week. Comfort while watching movies when I am relaxing is a big deal.
That aside, I have a question. Why did you pick the CQ6 over the MX6? Even though I am not fully read up on these two systems, the MX6 seems to be a more updated version of the CQ6. It has the dual channel memory, fasters FSB, allows for 2 hard drives vs one. To me, if I was looking at the two, I would more than likely go with the MX6.
That aside, how mobile are you talking about? The difference in weight is about 2 lbs, and yes, with the 17" screen, it is a bit larger. But it is still completely mobile, just as my EX7 is. But a difference is the battery life. The time on the CQ6 and the MX6 is much greater than the AX7. If you are one of those who are away from electricity when you are out and about, this makes a big difference. This should be something to think about.
Wish you the best in your decisions and if you have other questions, please feel free to ask.