JM Labs Altos

Just looking for peoples opinion on the JM LABS ALTO, are they bright with that BE tweeter, I own Pass labs 350.5 Amp and X1 pre-amp with Nordost SMP speaker cables and Mezzo at present and thinking of moving up a model, I have heard them years back, thought they where great and thats why I bought the Mezzos 2nd hand and still love them to this day, what am I going to gain or should I be looking else where?
There is nothing bright about the tweeter. The Be tweeter is a marvel, clean and clear and uncompromising. That neutrality reflects the system and the recording; if the system or the recording is bright you'll hear it; but don't blame the speakers.
Yes they tend to be on the "bright" side of neutral just as silk domes tend to be more laid back.
The Altos can be fabulous but you must make sure you have the proper room for them. The BE tweeter could be bright in a poor dampened room and bass will not be full if attention to traps and absorbtion are not correct. Mezzos cabinet have higher resonance and are not as neutral as the Altos therefore are not as critical to listening enviroment.
I own a pair. I suppose it depends on a number of factors. I drive them with a Boulder 1060 connected with NBS Omega 1 speaker cables. I run my Wadia 861 straight into the amp via Tara Labs 0.8 balanced interconnects. I wouldn't consider my system warm, but it has tremendous detail. The Alto Utopia BEs are phenominal loudspeakers. I've tried many cabling combinations, but this setup gives me I want. I like them so much that I'm considering moving up to the Novas because I have the room and like what the Utopia BE series offer and want to go to the next level.