I want to know whether to buy this game, and does it feature good controls?

It is a console to PC port and they didn't update the controls on the PC at all.
They are actually quite playable, although the camera does present some problems here and there; Since looking around was originally planned for analog controllers, when you look up or down with a mouse, the screen automatically slowly resets to center of the screen, so you have to keep moving the mouse up or down. This is because of the analog controller sends output constantly, while the mouse sends it only when moved.
Aside from the control/camera problems, the game features a nice storyline and a good pacing between stealth and action missions. The half-electronic, half-orchestral soundtrack is pretty amazing as well.
If you don't easily get frustrated with some minor control problems (read: have enjoyed other console ports on the PC before), it's a fine shooter, well worth the purchase imo.

The story is fantastic and apart from the dodgy camera. ( which I myself dident find too bad but other do find it a pain) the mouse/keyboard control is more than adequent.
so just to reitterate.
the story is fantastic and worth putting up with the minor niggles.

Given the control issues does the game support USB controllers like the XBox 360/PC controller?

Not directly, as far as I know (at least I haven't seen anything in the options menu).
But you can use a joystick with either , which is free, but not as customizable as [url=http://www.pinnaclegameprofiler.com/]Pinnacle Game Profiler, which has a 30 day trial (it's also quite cheap to buy if you play alot of PC games with a gamepad.

I have this game on xbox and it is fantastic, it is a bit tedious when you have to continually hide though, it's basically metal gear solid with telekinesis involved

Most of the controls are fine, but I found the mouse movement/speed to be really really sluggish.

Frankly, I stopped playing it halfway through. The controls are just slightly complex. This wouldn't be a problem if it weren't coupled with a HORRENDOUS lack of save game.
Don't get this game if you are easily frustrated.

My interpretation:
It's old school hard. As in, you can't win it just by playing long enough. If that's a shock to you, well, that's what we mean by "old school". ;)
It's hard. I love it.

Psi-Ops is freeware and allot dumber than Second Sight. It's still fun though in a stupid generic action movie sort of way.
Second Sight has a great story, and I didn't really have any trouble with the gameplay. The characters were also quite likable. Free Radical is dead now, so there's no chance of a sequel, but at least it doesn't end on a stupid cliffhanger like Psi-Ops... which still doesn't have a sequel either.

oh man the story in this game is amazing!! the gameplay is very good to but its the story that really sells this game.. I was dumbfounded by the twist at the end.. it was AMAZING

i thought this was a great game actually never noticed many problems with the camera too much at least not enough that it kept me from playing
as for the stealth thing i've gone through it a few times stealthing as much as possible and just slaughtering everything in my way both work but a healthy mix is more fun for me lol
(sometimes i'd let the cameras spot me just so the nice guards would bring me some more guns :) lol)

I feel the same way. I played the Gamecube version of Second Sight and liked it. But Psi-Ops just blows it away. I rocked Psi-Ops on PS2.
It should have fared better commercially than it did. Like Time Splitters, its publisher half-ass marketed it while throwing boatloads of funds marketing "sure things".