I've been using the Saitek Pro Flight 3 Lever Throttle (
http://www.saitek.com/uk/prod/quad.html) for about a year now and can't complain. It does look a little cheap considering the price tag but it's sturdy and gets the job done.
My joystick has two levers which I assign throttle and prop pitch so currently I use the controller for radiator and mixture. It also has 3 buttons under the levers which can each be assigned two commands - I find that handy and have a bunch of things controlled through these e.g. flaps etc.
All in all I find it useful to have, it's sturdy and I've had no problems with it. In my opinion it's a little expensive for what it is but I'm not sure there's much out there available to rival it?
Also, there is a thread on this forum discussing throttle quadrants which might be worth a read if you haven't seen it (
http://forum.1cpublishing.eu/showthread.php?t=28859)