I had a few friends with the X56 and they liked it better than the X52. Build quality varies with both of these.. some last forever, some last a few months depending on use. The only thing most can agree on is the T16k going bad within a year or so, starting with the either the 'twist jitter' problem or slowly increasing centering issues.
Out of a choice between those three, I'd choose the x56. You can adjust your style/muscle-memory for a new stick, it's hard to adjust for random/broken inputs.
All that being said, I'd start saving for a 'good' stick. Virpil and VKB make very nice stuff with a lot of customizable handles and options. You can get one stick, that will last for years and can be modified and upgraded. I understand that taking the dive on a $400 joystick for gaming tends to get you looks from family and friends, but when you've bought 3 T16k's and one or two X-series joysticks.. who spent more money ? Throw $10-20 a month into a cookie jar and treat yourself next Xmas, or keep adding if the Saitek still works.