If you deliberately shake it, it does wobble. But it's not really a problem for most uses, though I wouldn't want to use it for hand planing.
There are accessory brackets to make it more rigid.
The rail supports could be better, and there are some after-market products, but again, the rail is supported well enough to work fine. I think most of the stories of excessive play are internet hype.
The MFT is a very useful work table, meant to be somewhat portable, and be flexible enough to support work pieces in a variety of ways. It does that pretty well, but it's not unique, there are cheaper alternatives, however.