The official advice from the corsair staff is not to update the firmware unless you absolutely have to, vanity is not a necessity. The latest (2.2.0) Link software needs the firmware on H100i/H80i to be updated to 1.0.4.
The units are currently still being distributed with an earlier firmware so the earlier software is needed (2.0.16 beta). We've all got our fingers crossed that there will be another software/firmware released before the new year considering all the damage being done.
As for the fan noise SP120s are defo the way to go. Loads quieter than the stock fans.
Advice for peeps who have one:
1. Before installing hold the unit by the rad so the pump hangs and give a gentle rock/shake for about a minute before installing (sends any air to the rad).
2. Run the unit externally first to check for noise.
3. If you get a rumble noise do not update the firmware as it'll turn into a high pitched whine.
4. When installing the software, unless you have an AXi PSU do not let the unsigned drivers install (they're only for the PSU)
5. Don't expect to see 'Corsair Link(TM) USB Dongle' in device manager. These pump units are supposed to run as a 'HID Device' with microsoft drivers. If you still get the '!' warning triangle' update the drivers through windows update.
It seems a real shame the software doesn't come with these units. But even worse - there's no instructions with them.
I'm waiting for an official statement. As soon as I get it I'll post it up for y'all
My thoughts: Don't be put off by all this. These units are great and to be honest for the volume being sold there aren't really that many bad units turning up