Is the Ice Jet X3 an air conditioner?

No. It is an evaporative cooler: a fan blows air across a wet pad. It does not use refrigerant and cannot chill a room the way a window or portable AC does.

Does it work in a humid room?

Poorly. Evaporative cooling relies on dry air, so in muggy conditions it mostly just moves air and adds moisture. It works best in hot, low-humidity climates.

How close do I need to sit?

Within a few feet. The cooled breeze is personal, not room-wide, so it suits a desk, bed or couch rather than cooling a whole living room.

Do I have to add water or ice?

Water is what makes it cool; without it the unit is just a fan. Ice or a cold pack in the tank gives a brief extra chill but does not change the overall cooling.

How does it compare with a tower fan?

A tower fan moves more air across a room and never needs refilling. The Ice Jet X3 trades that reach for a cooler, moister breeze aimed at one person.

Only if you want a small personal breeze in dry heat and accept fan-level noise. If you need real room cooling or quiet operation, a fan or a true air conditioner serves better.