Comparison between The Sims 2: Open for Business and The Sims 3: Ambitions

Features in both

Inventing
Stores
Cash register
Salon
Robotic Sims: Simbot in TS3:A, Servos in TS2:OFB (As well as Servos In MTS and Plumbots In TS3:ITF ).
The ability to view a sim's workplace.

The Shopping District sub-neighborhhod (Bluewater Village) and the ability to attach more shopping districts for a main neighborhood
Elevators (in The Sims 3: Late Night)
Kite
Other robots
Bakery, though some baked foods exist in The Sims 3, and Ambitions allows a bake sale for children only
Floricultures
A Lemonade stand (Replaced by bakery stand, and return as premium content for Monte Vista)
Fully controlable businesses (the ability to view the business,hire employees and assign them to jobs) (replaced as Store Content)
Rally Forth Object and Death by Rally Forth (Replaced as death by ranting in The Sims 3: University Life)
Business Perks, Costumer Loyalty and Setting Prices (replaced as Store Content)
Flower Arranging and Flower shops (though buying flowers and giving them returns in The Sims 3: Generations)
Talent Badges such as Cash Registing, Restocking, Cosmetology and Toy Making etc..

Laundry (new in The Sims series)
Tattooing (Some outfits from The Sims 2: University have tattoos with clothing)
Firefighter, Private Investigator, Architect, Ghost Hunter, and Medical career
Professions
Trampoline (in The Sims 2 for PS2)
Gnubb
Sculpting
Expanded inventing
Skill careers (Self Employment) such as Inventor, Gardener, Photographer and Angler
Time Machines and Miners
New neighborhood: Twinbrook which is not a sub-neighborhood (Bluewater Village)
Junkyards, Hangouts and Laundromats
Scrap
Education career (In The Sims 2: Seasons)