Warbuggy
This is what happens when you take a regular Dune Buggy and an Imperial Tauros before smashing them together and chucking them off a mountain. The Ork Warbuggy is a two-man Ork fast attack vehicle. Though they come in all shapes and sizes, a standard Warbuggy has a 4 wheeled low-riding chassis and a supercharged engine that enables it to zoom into battle at incredible pace making them incredibly popular for the Speed Freaks. As a result, Warbuggies are ideally suited for the ash wastes and silt flats of Industrial Worlds. It should be noted that the model is relatively outdated compared to... the entire rest of the army list, excluding the Wartrakk. This shows through with the wheels and the orks themselves, both of which being a bit more bland than other ork vehicles. This sort of thing is present in other armies (some of which are almost entirely composed of outdated models *COUGH COUGH* Sisters of Battle *Cough Cough*) but considering the general quality of the rest of the Ork List it is especially noticable here, with the old models being extremely fucking boring. Kitbashing is STRONGLY recommended.
Those Speed Freaks who own Warbuggies will inevitably group together in ramshackle bands that rampage across the battlefield, blasting away at anything they can like they are in Mad Max. There are various patterns of Warbuggy, such as those armed with Rokkit Launchas or Skorchas, though all of them have a speed-crazed driver at the front and a heavy weapons gunner in the back. The weapons used by a Warbuggy are normally twin-linked so that the inherent Ork inaccuracy can be offset by a higher rate of fire, and a full horde of Warbuggies has more than enough firepower to mow down enemy platoons or blow apart a tank. Of course they are lightly armored, so anything from a flashlight to a stapler is enough to make this ramshackle vehicle fall apart.
Tabletop
On tabletop, Warbuggies are possibly one of the most cost-effective and popular fast attack vehicle for the Orks. They are fast, and have decent, twin linked firepower that's as strong as most anything in the codex. Being so zippy it's easy to zoom around for side and rear armor shots, which actually might hit due to the twin-linked.
Some players like to run their Warbuggies as singletons, so the squadron rules don't apply. Most folk don't find an evil ramshackle go-kart too threatening and they tend to underestimate it and ignore it in favour of the Battlewagon nearby. So you can use this as a good advantage to sneakily go around unsuspecting enemy vehicles too preoccupied with the giant DISTRACTION CARNIFEX of a Battlewagon and attack their rear.
They are low enough to gain cover from grots, but the gun is high enough to shoot over them with relative ease, and buggies (especially single ones) are very easy to hide or gain cover with.
Also, and most importantly, they are dirt fucking cheap for what you get, and can shrug off most small arms fire (Barring massive quantities or especially powerful guns) whilst being relatively fast and nimble.
There have often been a rivalry on whether a Warbuggy is better then a Deffkopta or vice versa. However, despite this, there is a saying that if you aren't using Warbuggies in your Ork playlists, then you are doing it wrong.