That seems like an odd comparison. So you went with the 600i, which I would say would be an embarrassment if the Moon didn't win out there at twice the cost.
I would have suggested you try the Naim separates vs the 600i at that price point.
It really comes down to system matching, but I would have been more interested in a shootout between the 340i and the Supernait 3.
I've heard those both with Spendor A7 and D7.2. Both sounded fantastic, but to my ears the Supernait 3 sounded better with the Spendor D7.2, and the Moon 340i drove the A7s better.
It's a tough call, but you should go with the ones that drive your speakers to perform to your liking.
I would have suggested you try the Naim separates vs the 600i at that price point.
It really comes down to system matching, but I would have been more interested in a shootout between the 340i and the Supernait 3.
I've heard those both with Spendor A7 and D7.2. Both sounded fantastic, but to my ears the Supernait 3 sounded better with the Spendor D7.2, and the Moon 340i drove the A7s better.
It's a tough call, but you should go with the ones that drive your speakers to perform to your liking.