We've had this microwave for over a year now and only use the microwave and convection oven functions because our studio didn't have either.
The microwave power is 900W; unfortunately most ready-made meals only display cooking times for 800W and lower microwaves, so we just reduce the cooking time slightly. You are given the option of cooking at 100% (High), 70% (Med High), 50% (Med), 30% (Med Low/Defrost), and 10% (Low/Defrost).
For the convection fan oven, its 26L internal capacity is good enough for a small roasting pan. You are only given the options of cooking at 250C, 230C, 220C, 200C, 180C, 160C, 130C, 100C, 70C, and 40C. If you need anything in between, you're out of luck. There are times when we need to adjust the temperature in the middle of cooking, but there is no way to do this without stopping the cooking and re-entering the time and temperature. Then you may have to take the dish out as the oven goes through the pre-heat cycle (or leave it in if you don't mind your dish going through the pre-heating).
Overall it's a great device and has served us very well.