Oh my gosh, that's a wonderful rate. DO IT. We rented a mid-size SUV in mid-February and it was about $250 for the same length of time and I thought that was a good deal!!!
We never do the insurance, we don't do ANY of the extras. As far as gas, we use no more than one tank of gas and that's even with a trip to the beach one day.
On our first trip, we used buses. On all four other trips we have driven ourselves or rented. NEVER will we not rent a car or have our own car. It's just not how we want to spend our time.
Many people prefer not to drive while on vacation, but I guess I don't really understand that. For us, it's truly not a big deal and the advantages make it worth it.
One tip - when you check in to get your car, they may try the bait-n-switch on you. For example, we were supposed to have a Jeep Cherokee or something in that range. When we checked in, they said that we could upgrade to a mini-van for X dollars a day. We said thanks but no thanks. So they got us all set, told us which parking spot to go to, and wouldn't you know it - we got a MINI-VAN. It was a Kia Sedona and we really liked it, so we weren't disappointed about not having an SUV. But it's just the fact that had we said yes that we wanted to upgrade, we'd be paying a lot more for something they were going to give us REGARDLESS. Grr.