I haven't experimented with it myself yet but I've found that the thing makes so much damn noise that even if you don't see it, you know its around.

which is why they make you run to the enemy to blow up or l;eave it quietly behind them

I didn't read mostly any thing anyone posted here...
So I'm going to state that;
1. I disagree it's overpowered.
2. I disagree it's useless.

It's not overpowered because it's slow, clunky, hard to fly if you don't use it enough and easy to destroy if the enemy is paying attention (or has ANY bots).

It's not useless because it is VERY good for scouting players and getting them on a map, even if that FAILS and you're taking shots you can get in close range and detonate that mofo straight back to his spawn point. Then you can rush in, finish off the rest of the group and proceed to do your Op things...
I LOVE, I mean REALLY LOVE, the UAV. It's the best skill that came out in the pack. Because of this thing I've been picking Op as my starting class again in almost all maps. (Though I LOVE planting a napalm mine RIGHT next to a regular mine in a small hall with my Engineer... SO great.)

Agreed with OP. Personally I feel it fits better with an Engineer than an Operative. Most Operatives tend to always be on the move while most engys tend to guard their turrets and area.

I've found it to be exceedingly useful for clearing out rooms of guys as an operative. The operatives don't have a lot of offensive strength, the UAV gives them that while being more useful to the team with the enemy discovery. Honestly, as an operative, you spend a lot of your time waiting to kill your enemies and waiting for the right time to strike. The UAV fits in perfectly with that theory.

If the Engineers got the UAV it'd be significantly over-powered in tandem with their already powerful turrets.

But then again, now I can hack enemy turrets and use my uav to help hold an area. Operatives also have more defensive capabilities.

I've found the UAV to be pretty balanced. Regardless of how much damage it does, it's still less than even a mediocre player with an SMG is capable of in a fraction of the time.

agreed, it is overpowered, and people have figured that out. they are using them as much as possible now, even as a heavy i get killed by this little toy before i can react to it. all i been hearing today it friendlies scream UAV every 15 seconds