I finally got my ICX6610-48 set up (shoutouts and thanks to Fohdeesha for all the help!), and am definitely happy with my purchase so far. I sadly lost the PSU lottery and got the revA firmware versions, so I had to plug both PSUs in to avoid it sounding like a jet engine, but I don't think I can differentiate its fan noise over that of my R710's at this point. It's certainly wonderful finally being on a more modern managed switch OS (catOS is a bummer), and the copious amounts of 10GbE ports are enabling some things I've wanted to mess around with for a while.
Currently, my setup involves the following hardware:
Brocade ICX6610-48-E Switch
2 Finisar FTLF8519P3BNL 1GbE SFPs (1 in the Brocade, 1 in my Meraki MS220-8P)
2 Ubiquiti UF-MM-1G 1GbE SFPs (1 in the Brocade, 1 in my Meraki MS220-8P [unused currently])
2 Avago AFBR-703SDZ 10GbE SFP+s (1 in the Brocade, 1 in my primary use PC's Mellanox ConnectX-3)
2 Intel FTLX8571D3BCV-IT Dual-Mode 1GbE/10GbE SFP+s (1 in the Brocade, 1 in my gaming PC's Mellanox ConnectX-3)
1 Monoprice 2M Cisco QSFP-4SFP10G-CU2M Compatible QSFP+ to 4SFP+ Breakout Cable (3 connections in use, all to Mellanox ConnectX-2 cards)
Of note:
The dreaded Monoprice QSFP breakout cable slid in nice and smooth in the 40GbE breakout port I installed it in, and didn't really seem like it was binding or anything, but I haven't tried removing it. I should mention, my 1/2/2 port works _just fine_.
The Intel dual-mode SFP+ module I'm using is reporting as 1GbE even with the port set to 10GbE, but this may just be due to the link not being in use right now as I'm waiting on the OM3 fiber cable to hook it up with.
Rev. A PSUs are annoying
I had a hard time getting my VLANs working for a while, until I realized I needed to add them on my Meraki MX64 first. Why that was needed when the traffic shouldn't even be hitting it directly must be a Meraki thing. But it all works now!