I think anyone living or spending large portions of time in LOS should think about having the Dengue jab. I believe they are available privately here in the UK, probably for a considerably more amount than what you are paying.

MedConsult Clinic (www.medconsultasia.com) No I didn't wake up with 'drippy dick' or pissing razor blades! I've been using this clinic for chronic medication and it was time for a re-stock and also to get the second anti-Dengue Fever vaccination. So off I trotted to MedConsult which is located on soi 49/9, right in the heart of a very Japanese area.  The clinic is on the third floor of the Racquet Club, which is located on the 9th alley off soi 49. A good landmark is the Sumitvej Hospital, located on soi 49 just a few minutes before the alley 9. I'd recommend MedConsult as the main doctor there is a Kiwi lady ('Doctor Donna') and it is run along farang lines. I'd say that 99% of the patients are farangs and it is a busy practise focused on work medicals, vaccinations, aesthetics, prescriptions and STD check-ups!  It is low cost and so if ever you are in need of any of these services, I would recommend it, as it is highly efficient in my experience. (The blood tests etc. are a LOT cheaper than Pulse Clinic!). It is also open 7 days a week and has a big aesthetics section. I got the feeling it would be 100% fine to walk in there with a LB, no problems. SAG

On my recent stay at the mecure, I was at the front and on a low floor, I found it to be quiet in the room, i was surprised at how absent the noise was from soi 11. 

No problem with the cleanliness and getting a good sleep at the Mercure if that important. But do ask for a room at the back of the hotel to avoid the noise from Soi 11. The Hyatt is more central in terms of being close to CIB, Cindy's and WN. Mercure is barely 60-seconds from Cindy's and still an easy walk to the other bars. I've not stayed at the Hyatt Regency to given an opinion (I did stay at the Grand Hyatt Erawan), but it's your money and while you can expect better quality at the Hyatt, I would say its for you to decide if $150 a night is better spent on accommodation or entertainment. 

the carne asada with fries and the jalapeno (cannot find a tilde on my keyboard)  poppers are quite ok in Margarita storm