If you're 'going to listen to them' does that mean at the retailers place? If so are you taking your speakers or do they have your speakers there to demo with. The source is less of an issue as it will be a comparative test and you can make a decision between the amps based on whatever source they are using. But the amp has to be able to drive the speakers and more than any other component, there needs to be good synergy between the amp and the speakers.
I'm familiar with all but the Leema and each would be a fine if very different choice, assuming that each can work with your speakers (what are they?).
The Naim and the Cyrus offer upgrade paths via external power supplies. Both the Flatcap from Naim and the PSX-R from Cyrus are comparable in price, but Naim have far more headroom in terms of expansion and upgrades. Most people who start off on a Naim route end up much further down the road than they might have expected.
Whatever you do though, don't listent to either the Naim or the Cyrus with the power supplies in place as it's just going to expand your budget.
The Moon I am less familiar with but have heard it once or twice; more akin to the Cyrus than the Naim.
Take the music you want to listen to; the one you end up turning the volume up highest on is most likely the one you want!