The e-maxx is a great truck to bash around with. You can drive it off a cliff and it will still be going....Stay away from the lipo's if you just drive it in your backyard. They are great and extremely powerful batteries but you need to know what you're doing. As mentioned before, you need a LiPo balance charger, and a low voltage cut-off on your ESC (electric speed control) If you draw them to low it will kill the battery. I have seen them explode several times and it will destroy the car. (and your house if your a bit out of luck).
Try to find at least 4500 MH to get some running time out them. My e-maxx, with the upgraded Mamba Monster ESC/Motor will run 10/15 min on a 4500 MH or about 15/20 min on ther lipo's.
Try to stay away from the grass, it will suck your battery dry fast, and might kill the motors. (happened with Sam's Rustler). Climbing hills and dirt is where it's build for.. And, be careful on gravel......the emaxx will trow gravel like a shotgun.....
It's a great hobby. I started with the e maxx just to bash around and now we have a basement full of off road and on road cars. This is Sam's latest car:
https://lh6.googleusercontent.com/-TLqd_BtnFGg/Tsq4LdkqRYI/AAAAAAAAUk0/lBdb1_1KaJE/s640/IMG_1886.JPG