I haven't heard LM Audio, but my understanding is that they are a less expensive Chinese brand, that is aimed at people who like the Shindo/Leben type of sound but want to spend less money. In the US, they are imported and distributed by the same distributor, who definitely keeps a "house sound" among the gear he represents. Matt at Pitch Perfect Audio, who carries all 3 lines, has stated that as much as he likes the LM products, they are not really comparable to the Leben and Shindo gear, as might be expected given the price difference.
In terms of the Shindo vs. Leben sound - I'd say that Leben is a bit sweeter, and Shindo is a bit more layered and detailed. Shindo is generally a more punchy and dynamic sound than Leben, and is more to my liking - however, both work extremely well with Devore. It's a matter of how much you need in terms of dynamics and volume in your room.
Again, I'd probably shy away from a CS600 - even if it has a bit more power than a Montille, a Montille/Aurieges L is a better sounding combo at a similar price, and I suspect that the lack of power that you might occasionally feel would be offset by the fact that the Shindo combo has more layers to uncover as you listen to your music. And then if funds allow at a future time, you can upgrade to a bigger amp - which is a nice benefit of separates.
In terms of the Shindo vs. Leben sound - I'd say that Leben is a bit sweeter, and Shindo is a bit more layered and detailed. Shindo is generally a more punchy and dynamic sound than Leben, and is more to my liking - however, both work extremely well with Devore. It's a matter of how much you need in terms of dynamics and volume in your room.
Again, I'd probably shy away from a CS600 - even if it has a bit more power than a Montille, a Montille/Aurieges L is a better sounding combo at a similar price, and I suspect that the lack of power that you might occasionally feel would be offset by the fact that the Shindo combo has more layers to uncover as you listen to your music. And then if funds allow at a future time, you can upgrade to a bigger amp - which is a nice benefit of separates.