Most rooms are the same size within each property. Approx 290 - 390 sqft, depending on the property. Typically, the rooms with 2 Queen beds are slightly larger than the rooms with 1 King. However, that extra space (and then some) is used by the extra bed.

Accessible rooms may be the most spacious. In the prototype, accessible rooms have approx 120 additional sqft.

A few Alofts have suites, but it seems that most do not. Here are a few that do have suites:
Aloft Dallas Downtown
Aloft Leawood-Overland Park
Aloft Minneapolis
Aloft Washington National Harbor

Prototype PDF