The second RDX dropped the turbo four and moved to a naturally aspirated 3.5 V6 with an automatic gearbox, making the SUV calmer and more conventional. That makes it easier to understand, but not maintenance-free: timing-belt history, transmission condition and driveline servicing still define whether it is a good used buy.
A healthy RDX II should feel smoother and more relaxed than the first generation, with clean shifts and no sense of strain from the V6. Poor cars usually show vague records, delayed belt work and fluid maintenance that was stretched because the SUV kept driving well enough.