If you've stayed in boutique hotels in the states, especially in San Francisco, the B Hotel is everything most of those hotels aspire to be but fail. Clean. Attractive. Very helpful staff. Convenient to nearly everything. While there are quirks -- the shower in the tub takes getting used to, the lighting controls require the key card be left in a slot by the door -- these are all at least good intentioned (water saving for the first, power saving for the second).
This is very close to the Barcelona convention center buildings. Across the street is a big mall in the old bullfighting arena with great views on the top floor. Two blocks away is a very busy taxi stand, three blocks away to aiport shuttle buses. Buses and mass transit stations within 2 blocks. Starbucks on the ground floor with tons of space and good WiFi. As with most of Barcelona, multiple eateries and bars on the same block. A 'Super Merkat' steps away from the entrance and an urban grocery mart 3 blocks away.
Breakfast buffet is very nice, but pricey compared to nearby eateries if it isn't included in your package (US$40/person). Half of the breakfast area doubles as the business center once breakfast is over. Good chairs, decent amount of outlets -- but since it overlooks the Starbucks it has coffee-shop levels of noise. Not bad, and didn't interfere with web calls, just something to be aware of.
Overall, would recommend this with no hesitancy and would stay here again when we return to Barcelona