Tredmill Powerwalking: Advice

I recently joined the GYM ! WOW first time in my life.

Anyway, I have been reading a lot about power walking on the treadmill and fast results. Evidently powerwalking allows your HR to be in the fat burning zone.

I have been walking for 60minutes at 4.0mph at a 4.0 incline. I work up a sweat and burn around 500 calories.

Does anyone think this sounds like a good workout ?