I have one. Used it this weekend to power our camper. Gas doesn't last as long as the propane but has a higher amperage output. The propane is handy but costs more. 1.6gal gas tank gets you 7.5-8.5hrs at 1/4 load. Can't remember exact hours. Propane gets something like 12-14hrs at 1/4 load. What I found was either one will run out at the least opportune time. lol
Mine is a Champion dual fuel inverter model. Something like 3400-3500 watts. I believe I had around $1250-1300 delivered. You may find them cheaper now since they've been out a bit. I did have a couple issues out of the box. Thing wouldn't start. Tech support walked thru a bunch of things and ended up telling me to shoot starting fluid in there. Wasn't real keen on starting fluid in a brand new generator but that is all it took. I'll be contacting them again soon. It doesn't shut off when you turn it off. If running on gas you have to choke it to kill it. On propane you simply shut the valve off and it dies fairly quickly.