I'm pretty down on the LM Barcelona after my most recent stay. Didn't do much for platinum recognition. My advice would be that if you can get a Jr. Suite or larger arranged prior to your arrival, it's the best bet in terms of location and space. If you can't (which is highly likely in-season) I'd go elsewhere. The standard rooms are so small you'll be tripping all over your 20 mo old during your stay - think no place for a 20 mo / old to sleep that's further than 3 feet away from your bed. In that case I'd follow others' recommendations around the W or 4P.