1) China exercise bike are designed to be quiet but this only happens if it has a belted drive rather than a chain drive. Chain drive bikes are loud and they require maintenance. The belted drive bikes make very little noise and require no maintenance.
2) A console display is a great idea for a spin bike. Knowing what you are doing while riding is the best way to get your result. The display should have RPM, Speed, Distance, Level and Heart Rate. This Heart rate should work with a telemetry strap.
3) Should have a parts warranty longer than a year.
4) The bike should have an adjustable saddle and headset and you should be able to move both options forward and back and up and down for adjustment.
5) The bike has to be comfortable to start.
*Note: Bike seats are comfortable but it takes about a month to be comfortable. The bike seat doesn't conform to your butt, your butt conforms to the seat. This is why it takes longer. Remember if you ride a bike 3 times a week it will take you longer to get comfortable with the seat. Recommendation is to buy cycling shorts anyway as the comfort will allow you to spend more time spinning.
Sd has fitness treadmill for sale and welcome to your come.