Which Integrated for Magnepan MG-12?

I've just gone through an extensive integrated amp hunt (including most of the models you've listed). I settled on an Exposure 3010s2. My speakers are a tough drive like your Maggies. You might want to add it to your list. I'd place it on par with the Creek Destiny, but with a more balanced presentation. The Destiny tends to accentuate the top and bottom end at the expense of the midrange. The Bel Canto uses a class D amp which gives a very different sound The others are not in the same league, in my opinion.

Maggies are NOT a 'tough load'.
Low sensitivity, to be sure, partially made up for by being dipoles. Low reactance, too, which kind of means you don't need hign damping factor amps, (read TUBES).

'd' amps sound good with them. The W4S has balanced inputs which go well with a balanced CD player....like my CA 840c.

I sort of liked the 400xi Krell with panels at a listening session, but the darn thing just got so HOT I couldn't figure out where I could put it where it wouldn't cook itself.

I settled on a 'd' solution which gave very satisfying sound, had balanced inputs and is not only very nuanced, but has great pace, as well.

Now that I think about it, I did try the Bel Canto S300, but I still feel the Krell outperforms it with the 1.6QR. The Krell never really gets hot in my system. I also use the balanced inputs, but with the Krell SACD standard. It works really well.

Over the weekend we listened to the Bel Canto S300iU and Arcam A38 (the latter with the Arcam CD17 player), but in neither case with Magnepan speakers. The Arcam was OK, but not great (we do like the clarity of the Arcam sound, but it seemed a bit thin). We liked the cleanness of the Bel Canto - my wife, who's a classical musician, described it as "objective"(is that a typical characteristic of digital amps?) - but then the audio rep switched to a Rouge Cronus Magnum and the fluidity of the sound really struck us. And we later heard the LSA Standard hybrid amp (paired with the Cambridge Audio 840C) and we were very impressed with the deep soundstage, presence and natural sound of the LSA, which frankly I had never heard of before. So I guess now we're adding tubes/hybrids to our list (and perhaps bumping up the budget by a few hundred dollars!); we plan to see how the Rogue and LSA sound with our MG-12s. We'll also try to check out some of the amps you all have suggested. We welcome your continued comments and suggestions.

I listened to the 400xi for maybe 20 to 30 minutes at the hi end of moderate levels....the Krell was sitting out in the open on its own stand...nothing near it at all, above or to the sides.
The power supply got way hot. I could put my hands on it, but it was NOT very comfortable. The amount of heat boiling off the amp I would rate as 'lots'.

If it sat with shelving over it and restrictions to the sides, I'm sure it would cook in no time.

The speakers? some Maggie 3.6s and the music was just rock....