To be honest this is the best version on the Sims on Xbox 360. Sims 3 Pets could have been a DLC to this.
If your planning on buying the sims 3 for the holidays well I would get this version. why? because this version has less bugs that Sims 3 pets. If you played this version a lot,. you will notice the difference in bugs when you play sims 3 pets. (If they don't patch it before you buy it.) Yeah sims 3 pets has some new added features to it like the ability to take pictures and have cats and dogs and catch new insects..........other than that its the same game. Oh yeah I left out that pets has a new town and new Karma powers much bigger than this version (Sims 3)
The main thing you will notice in pets is when your talking to some one and your building up your communication with them (ok, sociable, Friendly,) you will some times disappear and will end up on the other side of the map. Then you have to run home, by the time you did that the communication is back at OK when you were almost on the Friendly level. This information is for people who have played the Sims 3. If your new to the Sims then I must say still give it a try!!!
Another thing I don't care for in Pets is that Jobs are cram together in one building. For example Police Career Military, and goverment are in one building. The Restaurant and the criminal careers are in one building together, The Spa Journalist and Business careers are together in one building. Etc etc
Its just nagging little things in pets that almost make it not enjoyable as this version. In pets when you get a boyfriend/girlfriend they are consider in laws to your siblings and you haven't even got married yet. I think they didn't test pets out before they release it. They just kinda copy and paste something and add annoying dog and cat to it. Trust me the pets get really annoying when they come in the bathroom with you causing your sim to be shame and get out of the tub not half clean. Then you have to run your bath water again and get back in the tub to wash.
Sims 3 wins against Sims 3 pets. (unless they patch the game well!!!)