I had the two bows that CG mentioned, and yes, the MQ1 was quieter than the Maverick. I my current #1 bow is a Darton Tundra. With it, I have all the easy tuning, smooth draw, and performance of the CPS system in a bow that is right there with any I've owned for noise level, including the MQ1, Q2 XL, McPherson 38 Special, etc. The Mathews bows definitely recoil less than the Dartons, but again, my Tundra has very little recoil, and it bothers me not at all.
If you are buying used, there are other considerations. IMHO, the Darton Extreme cam system is definitely quieter than the Express cams. For a used Darton, I would want an '03 Avalanche Extreme, or an '04 Tundra, Avalanche, Maverick, or Typhoon. Dartons do not hold resale value like Mathews, so you can save buying a used, but like new bow. The older Express cam bows will be louder though.[&:] Still, the Darton CPS bows are very easy to tune with broadheads, draw very smoothly, and have good performance for the draw weight.
The Mathews bows hold value so well that buying a slightly used Outback or LX hardly seems to make sense, since the price is very close to a new one that has a warranty. Also, with the cams having no draw length adjustment, you have to be very sure you are buying a bow that really fits you in the first place. It seems that you can finally get the MQ 1, Q2, Q2 XL, and Icon for a decent price, as resale seems to have dropped on those due to demand for the Outback and Switchback. If you like low recoil and noise, it is hard to top the Mathews bows. I found the grips to be too wide for me, and tended to torque the bows much more than some other bows I've owned. That is probably a personal thing because lots of guys claim the Q series bows are forgiving for them to shoot. It just wasn't true for me, or I'd probably still have the MQ1.
As usual, it really comes down to personal preference. Both are good bows. I personally feel that I got the perfect bow for me in the Tundra. Nice to see a broadhead tipped arrow fly just like a field point and hit the exact spot I aimed at out to 40 yards. (when I do my part, that is!)