Magnepan evaluation

I'm considering trying out the MMG model from Magnepan's website. Will my McCormack DNA .5 power them OK, or should I get a more powerful amp like the Classe CA-300 or the ARC D-400II in order to give them a fair evaluation. Also if I like them a lot I will probably send them back and upgrade to the 1.6 or 3.1 models. Then I know a very powerful amp is needed. Has anybody heard the new PS Audio Gain Cell amps?

PS: room size is 17 by 25

You may also think about the MG12 since many say that they are in some way better than the 1.6 and a bit easier to drive. I have a Portal Panace integrated that I am going to try and I think it will be fine. I actually have used a Dynaco St-70 at with pretty nice results at moderate level.
I am currently using a McCormack DNA 0.5 DLX with Maggie 1.6 QR's. I love this combination. I'd say don't be afraid to go with your McCormack until it proves itself not up to the task for your room and listening preferrences.
My room size is about 16 x 22. I listen to a lot of chamber music, although I also listen to a fair amount of hard core orchestral stuff (Mahler, Bruchner, Shostakovitch). The DNA 0.5 does a much better job overall with the maggies than my previous amp, which had 2x the power rating of the 0.5. Only very rarely do I notice a little compression that I don't remember with the other amp. I'm thinking about buying another DNA 0.5 and biamping rather than give up the sound I'm getting now.
I am driving MMGs with a 35 watt tube amp with no problems and before that had no problems with a Linn Classik, which I believe was rated around 60 wpc. I would think the larger maggies would need more power, though. You might want to run a search over at the AA planar forum on the DNA and the 1.6s. Some amps seem to work a lot better than others, regardless of specs.
With maggies, the more power the better. I've found that a lack of power usually can mean a lack of bass.

Personally, I would like the classe for the power as well as the "softer" top end. The maggies can be bright with the wrong amp due to the ribbon tweeter.

Final note: Maggies can be great as long as you are in the "sweet spot". If you've never owned them, you should give a pair a listen first to see how drastic the sound can change by moving 2 feet.
I second Elevick -- finding the sweet spot is critical. It can be frustrating or fun -- depnding on how you approach it. Positioning the Maggies is, in many ways, like focusing a camera lens. It takes small adjustments and lots of listening. At first this was frustrating but then it became another of my joys of this hobby. Once you get it spot on, the sound is pure magic.