I’ve spent a lot of time in the last few years bouncing between London and Spain (principally the Balearics, Madrid and Barcelona).

MO is the best in Barcelona, no doubt, but it’s a pretty mediocre MO / Barcelona is a terrible market for luxury hotels, so if the premium over other hotels is large (which it often is) I’d be tempted to skip it. The EDITION is probably the next best hotel in Barcelona and I also like Serras.

If you plan to stay in Palma on Mallorca, both Sant Francesc Hotel Singular and Can Bordoy are excellent.

The one thing I can’t cover is the child-friendliness of the above, but suspect La Residencia will be a lot better than my Palma suggestions above with children.