I did look into this amplifier, and it does have a few things going for it: Tone audio imports does import and distribute some truly excellent sounding products, and the build quality does look fantastic, especially for the price at least from the outside.
However, does it sound better than another brand is still only answered by a direct comparison, amp vs amp, and then it will come down to what you prefer.
Rogue Audio and Prima Luna are both highly rated products and the Prima Luna does have many similarities in design to the LM amplifier, so again, if you are not convinced just by listening to the LM amplifier without any comparisons to any other products, you are still going to wonder if any of these other products are better.
However, again the better issue is still subjective and then better in what ways? I would think It would be virtually impossible to a/b all the amplifiers you mention.
What I would then recommend would be to listen to the LM amp and see how well it compares to a much more expensive tube integrated and if the LM comes close and sounds good with your speakers just buy the LM.