We stayed at DELTA from 19th through 21st of april. Although staff is reasonably friendly, I would not stay there again on a business trip; reasons:
1)- Internet connection is not available in the rooms. They have an "open access" only at the lobby, and it has lots of incompatibilities (many people were cursing with their laptops accross the lobby sofas; I was not the only one). Else the signal drops all the time;
2)- Front desk personnel is not efficient on business center resources, such as fax (neither of my fax transmissions ever went through), photocopies etc.;
3)- Telephone operator is not very efficient, except if you speak fluent spanish (which is my case; but my wife got there a few hours before me, and they could barely communicate with her, which is quite unsatisfactory, considering our mother language is brazilian portuguese - very similar to spanish, in many senses).
Other than that, breakfast is good, rooms are comfortable, shower is OK, amenities idem etc etc.; summarizing, if you are going for a business trip, I suggest you consider other options.