Saitek makes a good product and I used to love my X45, but I'd go with CH gear simply because there has been an X36(?), X45, X52, now this X55... And the pattern suggests there will be new models down the line.
Compare that to CH which has been relatively unchanged in... Forever.
Why does this matter? Muscle memory. It is a complete pain beyond words to relearn muscle memory, especially if you're good enough where you're riding the edge in fights and fluidly using your HOTAS to full effect. Every single time you switch joystick models you have to reinvent the wheel. They are not the same. Buttons are different places, springs are different tensions, etc.
When/if your CH products wear out, you'll be able to buy the same exact thing down the road. When/if your Saitek wears out, the model might be discontinued and then it's ebay or you're out of luck.
YMMV.