I've identified five types of robos currently.
1: Wheelies - traditional wheel-and-armor guncars.
2: Floaters - add rotor blades, stay a few meters above the ground.
3: Flying Machines - jets and more jets to keep aloft and fast.
4: Hovertanks - uses rotor blades, but is too heavy to lift itself, effectively dragging along the ground.
5: Static structures - no propulsion, intended to sit still and cover a base.
Wheelies are pretty mobile and can range from fast buggies to heavy tanks, but are generally heavier, tankier gun banks used to soak enemy fire and return vollies. They have the advantage of durability and firepower, but sometimes lack speed or maneuverability. While easy to build and control, they're also prone to have heavily armored ones getting stuck on the terrain.
Floaters are also very easy to produce, as the rotors will generally stabilize themselves without having to worry about placement much. They can lift and descend, allowing them to move and fire over obstacles, especially descending cliff faces that would hinder wheelies, while are somewhat unable to climb. They can approach the same level of firepower and armor as wheelies, but are generally smaller, and become very obvious targets when lifted.
Flying Machines are built for hit and run tactics, utilizing jet engine speed and lack of restrictions to rise beyond weapon range and make 'bombing runs' to hit wheelies and floaters while escaping return fire. They are extremely vulnerable, as their components are almost always perfectly exposed, and pack fewer guns, but have much higher speed.
Hovercraft pose as more maneuverable wheelies, they use rotors but cannot lift, instead scraping against the ground at slower speed. They can have perfect 'wheel' coverage, blocking all fire as they can be built as 'sliding bricks' with no openings to hit the propulsion. Despite relying on rotor blades, they can be built to roughly the same size and firepower of a wheelie, but are almost immune to getting stuck on terrain and can even function when flipped.
Static platforms are generally a bad idea. While potentially massive and incredibly armored, they demand that the craft be built large and cover all angles with guns, or have a few guns with full rotation. They've extremely prone to falling over at spawn, and can have the enemy come in from unusual angles. A static platform of sufficient size could have rotor blades built underneath and function as a hovercraft instead, or 'sliding fortress'.