@havanesefluff You don't need to apologize for being indecisive. After all, it's a lot of money to spend. The more expensive Inspiron is still an Inspiron, with some of the limitations (especially cooling) of the others. Its dedicated graphics card would help, for sure. But an MX330 is really about the slowest dedicated card of the current generation. A 1650 is something like 300% faster in gaming. A 1050 ti mobile, which was released three years ago and has during that time been the de facto minimum requirement for running all Sims 3 packs together on ultra settings, is over 200% faster.
The question, when running Sims 3 on a lower-end graphics card or chip, is whether lowering the settings will be enough to compensate for the slower card. From what I've seen, there's not a lot of data on the MX330 specifically, but slightly older MX cards have definitely struggled to handle the game, even with only a few expansions installed. But there are probably also people who run some EPs, or maybe most of them, well enough to not complain.
I know this isn't the definitive answer you're looking for, but the thing is, you never really know for sure how well a given computer will perform until it's in your hands and you can test. There will always be a bit of variation from one machine to the next, even within the same product line, and more fluctuation when you start to factor in drivers and other internal settings that can affect how the hardware performs. Especially with hardware that's already borderline (or lower) for what you want to do, it's really difficult to predict exactly where the system will fall on the spectrum.
Additionally, individual players have different tolerances for low framerates and general mediocre performance. Some find 30 fps and choppiness when moving the camera to be a slight inconvenience; others find the game much less enjoyable; some get headaches and can't really play at all like that. That's something no one else can predict; the only way to find out is to play for yourself.
For people who already have a weaker system, of course it's fine to try out the game and see if they can make it playable. But you're in a situation where you can get a much stronger laptop, one where as long as the product itself isn't defective, you shouldn't run into any issues with Sims 3. On the other hand, maybe the other features of the Inspiron are worth the risk that you won't be able to play TS3 the way you want. That's your call; I can only tell you what might happen either way. And for all I know, this particular Inspiron would run the game perfectly fine for your needs. But you won't find out whether that's true until you've already spent your money.
As for the open-box model, I wouldn't normally get a laptop that wasn't new. But since this one is certified (not to mention still under warranty), and backed up by a physical store that would presumably accept returns if the product was immediately defective, it's much less of a risk. For $90, it's definitely worth considering. I'd say it's a close call, although if the money isn't critically important, I personally would still go with the new option.
