Is the 73-pint daily rating realistic for a basement?

No. That figure is measured at 95°F and 90% relative humidity, which is much hotter and more humid than a normal basement. In a cool room expect a fraction of that, closer to what a 20- to 30-pint unit delivers.

How loud is it really?

Costway rates it at 44 dB or lower, which is about the level of a quiet conversation. Compressor dehumidifiers usually get louder as the fan speed rises, so the low setting will be the quietest.

Can it drain continuously without emptying the tank?

Yes, a drain hose is included. It relies on gravity, so the hose outlet must sit lower than the unit, such as into a floor drain. There is no pump to push water upward.

What rooms is it best for?

Small to medium spaces: basements, closets, laundry rooms, storage areas and bedrooms. It is rated for 41°F to 91°F, so it handles cool rooms better than many budget units but is not a cold-weather desiccant.

No. It is gravity-drain only. If you need to lift condensate up to a sink or window, you will need a separate condensate pump.

How heavy is it to move?

It weighs 31 lbs and measures about 13.5 by 9.5 by 22.5 inches. That is manageable for one person but not something you will carry up and down stairs often.