I've owned a few of the above and would rate the AX7e on top, 6300 second, luxman next, and last the Sim I5.
Ayre is clean, clear, musical, powerful. A little thin if your speaker is thin.
6300 warm, not as focused, good power and looks, a lower-end mac, but still a mac!
Luxman is a little too rolled off, relaxed, awesome user interface, great for that speaker that needs some loudness, nice phono. Less clarity than mac. The next step up on Luxman gear kills all but is $$$.
Sim, I wanted to like but felt too much grasp and control and not enough flow. Dry. Perhaps this is the amp I should appreciate the most because it is opposite my taste!
Never heard of Atoll but hope it works out.