McCormack DNA-1 vs. Adcom GFA-5802


Relative noob here. I'm looking for a new (used) 2-channel amp to power my new Polk LSi9 bookshelf speakers. I've pretty much decided that I want to get the McCormack DNA-1. I've considered the Parasound Halo 23, as well as the Adcom GFA-5802, but it sounds like the McCormack DNA-1 is the better amp, according to a number of folks (unfortunately, I'm unable to personally listen to any of them).

My question is this: if the McCormack is the better amp, why is it priced around the same place as the Adcom and the Parasound in the current used market? I realize that the Adcom has a bit more power, and Parasound has made some great amps, but people seem pretty unanimous in preferring the DNA-1 for sound quality. What gives? Am I missing something? Is the used market just not as rational as I thought it would be, or has the superiority of the DNA-1 to the Adcom GFA-5802, and the Parasound Halo 23, been overstated? Is it just a matter of taste? Preference for the DNA-1 seemed to transcend mere fanboy-ism.

Thanks for any input.
bthogan
A follow-up:

A bit of research has convinced me that you're right, Mr. Tbromgard. The DNA .5 looks like it might be just what I'm looking for: 4 ohms @ 200wpc. Furthermore, a number of people think that it has better sound quality than the DNA-1, in smaller rooms, with smaller speakers and at lower volumes (my exact situation). Might even be cheaper. Unfortunately, there are none to be found at the moment. If one should become available some time in the next month or so, it shall be mine.
I have had great luck posting a "Want to Buy" ad in the Audiogon Classifieds. I bought an Audible Illusions Modulus 3B preamp and a Musical Fidelity V Link 192 that way just recently. A dealer contacted me and offered me the V Link192 for the 399.00 list price and told me I wouldn't find a used one because they are too new. Two days later, I was offered a 2 week old unit for 275.00 from someone who saw my ad. Of course I jumped on it.

Give it a try, it will only cost you 4 bucks.
Good luck Mr. Bthogan. Steve McCormack is very accessible and will answer questions and is available to perform mods if you like. I know from experience.
Possibly with my experiences I can concur and help you with your decision. I have owned all versions of the DNA 1 all the way up to revision A gold with a Plitron transformer. I also own the Adcom 5800 with upgrades performed by Musical Concepts. I was going to detail the differences between watts/damping factors of each and how they translate into the LF response and soundstage in my large, inefficient, 4 ohm speakers in a large room at good volumes but that is moot in your system.

You will be happy with a DNA of any ilk imho, and I hope you find one that is a deluxe or up to revision B status to acquire. I found that is the best money spent for an upgrade level.

Don't shy away from an upgraded Adcom as they are very nice compared to a stock/entry level DNA and are not high priced. I have dealt with Steve from SMC and John from MC and both are great folks and put put out quality upgrade work that still resides in my systems.
I agree - if you can wait for one you should pick up a used DNA with a Rev B or better upgrade. The difference between the quite good stock amp and the modded ones are startlingly better. Of course, those modded amps go quickly and don't come up for sale as often, but you will save quite a bit over buying a stock amp and paying for the modding yourself.