We stayed at Le Meridien in early January (during the still on holidays in Spain phase) and did not find it as crowded as we expected. Lots of vendor booths and one off sideshows impeded the walking flow down the middle walkway.
We had a 'Ramblas' facing room and found the sound proofing to be superb.
Worst part of the location is the one way street where the front entrance is located- esp with cabs.