Mellanox Switch (SX6012) QSFP Breakout Compatibility

[herby]

I think I'm going to get a Mellanox SX6012 switch but I don't have any 40Gb NICs yet. I was wondering what experience people have had with different QSFP to 4x SFP+ breakout cables and Mellanox switches.

Since I've had luck with passive Cisco SFP+ DACs in my Connectx-2 NICs I thought I might try these:
I think these are QSFP28 rather then QSFP+ and likely incompatible:
Cisco Systems QSFP-4SFP25G-CU1M 4 x SFP-25G Cables | eBay

Any idea if Mellanox Switches are picky with passive breakout cables?

 

[herby]

So I'm chickening out, for now anyway, and just getting what should be a legit Mellanox MC2609130 breakout.
But, I'm still curious if something like a Dell DAC-QSFP-4SFP-10G or a Cisco QSFP-4SFP10G would do just as well.

I'll have to wait for a good deal to test something unofficial.