How large a room can it handle?

It is rated for spaces up to about 300 square feet. In a closed bedroom or closet it can hold humidity down, but a large open basement will overwhelm it.

How often do I empty the tank?

The 2.5 L tank fills faster in humid weather. Expect to empty it roughly once a day in a damp room, less in a dry one. It shuts off automatically when full.

Is it quiet enough for a bedroom?

The claimed maximum is 30 dB, which is close to a whisper. Most small dehumidifiers at this size are quiet enough to sleep near.

Does it really humidify as well as dehumidify?

It lists both modes, so it can add moisture in winter. Check that the humidifying mode suits your room, since small combo units often humidify weakly.

Can I connect a drain hose?

No drain hose is listed. Plan on emptying the tank by hand, which matters if you want it running unattended for days.

Is it worth it over a bigger compressor dehumidifier?

For a closet, bathroom or RV, yes: it is quieter and easier to place. For a whole basement or a persistently wet room, a compressor unit removes much more water per day.