I hate to admit it, but I am one of those guys that thrashes on rental cars.
My first was a early 2000s Chevy Malibu. The car wouldn't let you do neutral drops... I tried. It would just rev up, then when you went to drive it would wait until the RPMs dropped, then go into drive. I believe the car had the 3.1 V6 and it would light the front tires up around turns... think CV joint torture. I then found an area where some mud had washed up over the road. I knew I had pavement beneath it so I went over and over this area of mud almost getting stuck... until I hit solid ground and bogging out... the car was caked in mud... I just took it by the pressure wash place and make it look good on the outside while the undercarriage probably looked my 04 Z71.
My second was a 2002 Dodge Stratus. This car had less than 6K miles and was the biggest POS. Completely gutless. I ragged on it, but really could only get it to spin in gravel or grass. I was easier on this one, but only had it a few days.
My most recent was a 2006 Ford Five Hundred - or Taurus now. I had this car for almost 30 days due to a fiasco with Sams Club service center. I liked this car. It had a CVT transmission and was fun to keep it floored and the RPMs stay pegged for eternity. Rental companies will charge some rediculous price per gallon if you bring the car back with less gas than you left with it. In this case I was about to have to return the car, but it had more gas than it had when I got it. Would I get a refund... hell no. So I was making my commute to work in the morning and would be returning the car that night. During my compute I moved the gear selector to L and proceded to do 75MPH for around 15 miles at 6K RPMs all the way to work to get the gas needle where I wanted it.
In closing... I would never buy a rental car. My friends, family, and co-workers would never buy one either b/c of what they have seen done on my behalf.