Simguru Ryan & SimguruHauts(?)(Real name Aaron) were the hosts. Stream was 1 hour long.
Please note, these are just my observations from watching the stream live. I didn't have time to go back and count objects or scrutinize everything. This is a general overview of what happened during the stream in a mostly chronological order. The SimsVIP has the entire video you can watch and pick apart for yourself
Build mode
Styled rooms - at least 5-8 rooms per room category (bathroom, bedroom, living room, kitchen etc)
Styled room chosen had 3 preset color schemes you could choose from: mustard yellow, brown, tan.
3 presets for wall height - uncertain if you can manually adjust wall height
Can purchase individual objects from other styled rooms and drag/drop from menu into room you are building.
3 different door heights to correspond with 3 wall heights (small, medium, tall)
Foundation was added in after 4 rooms already built. Adjustable foundation height slider adjusts whole house at once. Different foundation cosmetic styles can be applied to different rooms of house.
Stairs auto adjusted to match building height. Can drag stairs wider/thinner. No need to place multiples.
Auto windows - Can place windows around a whole room at once, spaced evenly with click of mouse instead of placing windows individually.
Windows can be placed at different heights on the wall independently.
No supports needed to make cantilevers! Floating room shown. 2nd floor room was dragged off roof. Room was then floating in air with nothing underneath it. SimGuru tip: to increase height of a floating room, keep copying room on top of itself, then deleting room below it to make it higher.
Auto roof tool: eaves can be adjusted both at once or hold shift to adjust one side of roof.
Styled Kids rooms: 5 styles, 3 preset color schemes for each room.
Design tool: click on object to bring up a small menu of preset colors for object. Bed shown had about half a dozen preset color combos.
Styled rooms can be unlocked as career rewards. ex: kitchen for chef, artist's studio for artist. Rooms have objects pertinent to that career in it.
Anything you put on the walls can be adjusted in height.
Live Mode
Entertainment object called Motion Gaming Rig was put into room and Sim was allowed to use it. Full 3D gaming simulator. SimGuru avatar was playing a Tetris like game inside the simulator by actually placing virtual blocks on virtual columns with his hands.
Back to Build Mode
Object can also be moved out from underneath Sim when game was in build mode. Room was deleted with Sim in it when game was put back into build mode. (In Sims 3, this would have resulted in an object cannot be deleted when in use error)
Outdoor plants category can be placed on top of roof.
Fountain tool: Can drag out square shapes for fountain. Also has menu of lights and water jets for your fountains.
4 different light settings to view your lot in build mode to see how lot looks during the course of a day. Morning, Afternoon, Evening, Night.
Gallery
Can share whole house to Gallery or just a single room from the house.
TS4LiveStream is username to search in Gallery for anything uploaded to the Gallery from this weeks live streams. Anything uploaded to the Gallery (lots, rooms, sims) are automatically saved locally to your computer as well.
One Last Look at Build Mode
Resize cheat was used to make a tiny bowl of fruit from a counter top to a GIANT bowl of fruit larger than the house in the back yard. Cheat was also used on topiary elephant. (I don't know what the actual resize cheat is)