Be careful when doing "Catering", as you will be required to roll back to a certified commercial kitchen. You can be a "private Chef", but even then there are rules as to cooking on site and such. That said, it is much like the posted speed limit, it is only the law if and when you get caught.
Small parties and such should be no problem, but it is best to get legal.
Back that the original question, figure out what the end goal is and buy the correct cooker to solve for that issue. that includes figuring out use, need and budget.