...should I know before I purchase one. I know that it will be a gas guzler but how often do they breakdown

They should get about 16 to 19 mpg. They cost more upfront but are normally less to maintain and should run 3 to 4 hundred thousand miles with regular maintainence.Also have much higher resale value.Make sure you are ready to pay $.75 to $1.00 more per gallon of fuel.

I am a diesel mechanic and I own one. You can't beat them for dependability and durability. Fuel costs more but mileage is good. If you keep the oil changed and filters changed. (more often then a gas engine,) you can get up to 500,000 miles on one.They don't have an ignition system so you never have to tune one up. The down side is repairs are expensive when needed but doesn't happen as often as with gas engines. good luck