They're both worth getting. I haven't finished either game, so I can't talk about end-game value for either, but it certainly feels to me like Turing Complete is an educational game with puzzle components, while Shenzhen I/O is a straight puzzle game.

Both are a lot of fun, and very well-made.

Shenzhen I/O (like most Zachtronics games) has some nice worldbuilding touches like the printable datasheets for the made-up electrical components, and a barely-there programming language manual.