How good is the noise reduction on an XRackpro2?

We have two 12U XRackPro2 racks, one in a lab space one in the vestibule of my office. Both have less gear than what you're talking about (UPS, 1U Server, 12-15 drives, tape library) but I've been happy with their build quality and ability to isolate server noise. Mine are well tolerated by those who share a room with them and while they are much quieter than a regular rack, it's certainly not silent. In my office, the heat output requires leaving the AC on almost all the time, which further increases the noise level. Since you'll have significantly more disks (more heat & noise) your exhaust fans will run more and make more noise trying to vent all that heat.

Seriously though, I'm glad there's no rack next to my desk, especially not a heat spewing SAN cabinet. It's not unbearable, but if you think the noise/heat is tolerable, put the rack next to your desk not someone else's.