The Rover is TerraTrikes entry level model. You have the middle of the line with the 8 speed Nexus hub. The current MSRP is $1499. It was designed as a high seating trike for easy entry and exit from the seat. That means you need to be careful until you learn the handling characteristics of the trike because high seating trikes are much easier to tip if you go outside of the safe handling zone (be careful turning sharply). The brakes are Alhonga unless it is a much older Rover which came with Zoom mechanical disc DB-450. Either way it is about the most inexpensive set of brakes available. The brake problems could be poor adjustment or contaminated brake pads. If they have gotten contaminated with something like oil or grease, the only solution is to replace the pads. Adjusting them can be simple. The pads have to be parallel to the rotors. The advice from TT for a different model was to back off the bolts holding the caliper in place, put a credit card between the pad and rotor, squeeze the brake handle lightly and re-tighten the caliper bolts while holding pressure on the brake handle. The pads will be parallel to the rotor with proper spacing between them. The only other adjustment is adjusting the cable itself. There should be a barrel adjuster for that. As long as the brakes stop the trike and don't rub on the rotor as you turn the wheel with no pressure on the brake handle, you haven't over-tightened the cable. Riding a trike with one brake that works well and one that doesn't is dangerous as it induced brake steer when you stop. That means veering to the side with the good brake.
You can read all of the specifications for the current model here:
TerraTrike
There are a few concessions to meeting the price point above. It is a heavy trike (47 lbs) with a limited gear range (20-62 gear inches). That's OK on the low end but pretty limiting on the high end if you ride it often enough to gain your "trike legs". The TT that I once owned weighed 36 pounds and had a gear range of 19 to 98. I moved on to a different brand trike with a much wider gear range when I got used to riding mine.