We only saw one hover car from the aliens. We saw the Expendables use two armored cars in the second movie. Of course, the aliens also had those walking rocket launchers, but they were fairly slow and the Expendables have the firepower to take them down.
Not on the infantry level. The aliens guns were probably more powerful than conventional assault rifles, but not up there with some of the big guns the Expendables were toting around. The walking rocket launchers help, but they lack mobility, and again the Expendables have some heavy weapons that can take them down.