Totally agree with you! I like the LB6M, but I have never pulled the trigger on it. I have wanted 10G connectivity, but...
I have an existing Procurve 5400 series switch as my core network. Being HP, it too is picky on it's optics for any of the SFP+ that is stuck into it... Adding ports to it is very expensive. 4 ports SFP+ recently set me back $350+ship. That's a great deal in the HP world. So, need to protect the investment in that switch (it's got 10Gbe, 1G ports and compute blades..) It's not loud, and it's not hot, but it likes power...
I have Cat 6 wired in my house, so, this is the most inexpensive way to get 10Gbe to the Office. A pair of the US-16-XG running copper 10Gbe, and one of the US-16XG's uplinks to the Procurve. It all works. All that is about the same as the typical price of one 8 port 10-gbase switch (1 Netgear $950+Ship, 2 XG's + Blade + ship $950).
This would mean I would need the LB6M for just my rack in the basement. Good, but, means my workstation does not benefit at all from all the money spent. I already use Fiber Channel, so 10Gbe does not help on the data transfer side inside the rack, and since I would be limited to 1Gbe to any client outside the rack, it was a iffy purchase... combine that with high power and loud... LB6M is awesome, but it's a deal breaker in my particular case.
The other issue with the LB6M is they are Data Center products. They run hot, they run loud. I had a LB4M which I modded the fans on to get the noise down. The temperature was always just below the warning. After a year of running like that it just up and quit. Cannot blame the switch, since I modded the cooling, my own fault for putting it in a environment it was never meant to go in. I learned from that about the need for airflow, and even the need for air flow reversal at home, etc.
The offer for 24SFP+ ports, and 16 10gbase ports for 600$US+ship is awesome in my particular case, and no need to mod the fans in my case, since it is quite quiet (my fish tank pump in the office drowns it out...)
I can also confirm Arista original DAC's CAB-SFP-SFP-2M work in each SFP+ port.