just wondering if there are any, and if so what are they?(pretty sure i read somewhere that there were nice features) I thought about getting the game if it adds more to build mode

Architecture

*Open For Business adds Elevators to the game. Elevators must be repaired if broken, or Sims may plummet to their deaths when riding them. Sims can also "WooHoo" in elevators-- though doing so dramatically increases their chances of causing a fatal mishap.
*Domed, conical and octagonal roofs in different sizes are now available.
*Players may now build split-level floors, treated as a single surface.
*Awnings, which are constructed like decks and foundations, were also introduced in Open For Business.
*The game now features new windows, doors, floors and wall coverings.
*Apart from the new doors, they may now also be locked by a home or business owner, to either; the selected sim, family or employees only.

(Quote Wikipedia)