Your own set of goggles, even the cheapest will be much better at fog resistance then a rental set - they dont have hundreds of peoples dirty rags wiping them and destroying any existing anti fog coating.
When you have your own set, new or secondhand, do nothing to the lens other than rinsing with water & microfibre cloths.
Use 2 cloths - one a little damp to clean, and a dry one to finish.
When the anti fog fails, or isn't good enough (assuming the lens is still in good condition and its not time to replace) then go onto an anti fog treatment such as Cat Crap.
Regarding choice of goggles then the standard answer is to try some on. Get to a walkon and see what other people use & ask to try some on, check out shops at events or get to one of the paintball retailers shops.
I4s have a good design to allow airflow and prevent fogging, but this comes with reduced cover for the mouth depending on head shape and size.