They both get the job done.
But the cougar is more precise (has more than twice amount of "sensors" compared to a normal joystick) and has that lovely metal feel.
Only drawback is that the speedbrake button is not properly aligned with the pot (on some units), which will eventually break the button in 2, it is very difficult to explain if you don't own one yourself  

I've had mine for about 1 ½ years now, and I'm very satisfied.
an you imagine your arm will become tired when performing manouvers which requires long turns and climbs/descent?...that's what you get with a 14lbs joystick  

Here's how mine looks

I've had my X45 for over two years, and I've never even given one thought to a "cheap plastic feel".  It's just something that's never crossed my mind.  (Primarily because at $90, it wasn't as expensive as the Cougar, but I'd hardly call it cheap.  They've come down about $20 since I got mine.)

Most importantly, I've done some pretty extreme flying, and I've never broken any of the 18 buttons, dials, etc....