I like it. Although basically the same as the old X36, it incorporates a couple new things. 1. It's now a slightly shorter stick. The old X36 was almost a 2-handed joystick. The X45 fits in your grip a little better. 2. The old pinkie switch on the x36 was annoying, this one has a better contour. 3. Its got pretty lights.
Aside from that It's the same as the old X36. Its a good setup, with over 64? button combinations total. I don't really like the rudder rocker too much, but until I can find an old analog joystick, my CH rudder pedals are just sitting in the corner gathering dust.
It will take you a couple of days to get used to if you haven't used this type of setup before, but once you get the hang of it, you'll enjoy it immensely.
The only hang up is if your using win 2000/xp, saitek has been very slow to update its product support. They are finally getting on the ball, although the most recent version of their profiler software (2.7) I have found to be just a little buggy.
I owned my x36 for about 2 years, and the pots in the first hat began wearing out at about 18 months. So there is your life expectancy for it.
Oh, one other thing... its made for right handers. I am a lefty, and had to re-learn how to fly after I found out it was only a right hand stick. (back when I bought my x36) But now, its second nature.