I sell the InnerSound amp, so I'm not going to argue with any of the above posts! Since I try to avoid gushing too much over something I sell, I'll just thank Sc53, Iasi, and Pls1 for saying it for me.
So far none of my customers are using their InnerSound amp to drive Maggies, but it is quite happy driving Sound Labs, Acoustats, Martin Logans, and Quads. Roger Sanders tells me he has customers using the amp to drive Maggies, and since his policy is to always take back the amp if the customer doesn't like it, I presume the combination works well.
I have one customer who likes things loud - he regularly drives his Sound Labs to over 100 dB with his little InnerSound amp. This speaker is a beastly load - about 2.3 ohms in the midrange, and even less efficient than Maggies, and known for literally murdering lesser amps (I had a pair of 800-watt monoblocks puke on the carpet trying to drive Sound Labs at less than 90 dB). The InnerSound is among the very few 3-grand amps that really sound good with the Sound Labs, and is the only one I know of in that price range that is truly dynamic. To put things in perspective, I don't know of any competing amplifier at twice the price that does as good a job with the Sound Labs, and few at three times the price. This doesn't necessarily translate directly over to the Maggies, but it's a pretty good sign. If they sucked with the Sound Labs, they'd be much less likely to sing with the Maggies.
InnerSound dealers are generally quite comfortable arranging for in-home auditions, so you should be able to hear the amp without having to buy it first.
Best wishes to you!