I have and use both the XP-120 and the XP-90. As others have said, go with the XP-120 if you have the space for it.
The noise level will be determined by the fan you use on either cooler, so you can choose a fan accordingly. The Thermalright fan that you can buy with either cooler is not very quiet. I run Vantec Stealth fans on my two coolers and I'm very satisfied with the low noise levels.
Do some research on different fan makes and models, comparing airflow (CFM) with noise levels (dBa) and base your fan decision on that. Panaflo fans are excellent, but they have a noisy model also.
(edited to add
From Thermalright.com:
Recommended Fan
Maker: Panaflo (Panasonic)
Model: FBA12G12L1A
Size: 120 x 120x 38 (mm)
Bearing: Hydro Wave
Voltage: 12V
Speed: 1700 rpm
Air Flow: 68.9 CFM
Noise Level: 30.0dBA
Weight: 270g (9.52 OZ )