You probably want a gas generator since diesel smells terrible and you don't want that anywhere near your home.

You just need to make sure you get one that can run long enough without having to stop. Most portable can't even run an entire day. If you get a stand by generator, that shouldn't be an issue. But you might still need to take a break once a week.

In general gas generators require more maintenance and have a shorter lifespan. But you probably want to switch to another energy source all together. A generator is. only good for 10,000-30,000 hours. Which is 1-4 years if you are using it every day.

A diesel generator would last longer and is easier to repair. So if you plan on using a generator for the next few decades, get a diesel. But I would suggest adding solar power asap and then only using the generator as backup. That way even a gas generator could last 20-50 years.