The problem with some portable generators is, even though it may be rated at 3500w most don't have all that power available at one outlet. My home portable 5200/6000 gen can only put out 16A at the big outlet. Not enough for summer use. It pops the c/b if anything more than the a/c is running, especially a hair dryer or coffeepot.
last summer we bought a predator 8750. The big outlet is rated at 28A. I was skeptical buying it but after a few weeks of 24hr/day use I am impressed. I watched my volt & freq meters when the a/c kicks on and both never fluctuated more than 2 and only for a fraction of a second. In 24 hours (hot summer, 90+) it uses about 15-16 gallons/day and colder weather (In Dec) it used considerable less fuel (8-10 gallons/day, of course less if it doesn't run all day/night).
I think I bought it on sale for $529.