I've used Black Code as my go-to string since it was launched and feel like it's the best string for me on the market. I really enjoy softer polys, this feels so plush no matter what racquet it's in. Since using BC I've gone through prestiges, speeds and now xi 98s, I always come back to it.
I found Poly Tour Pro a really good string for me, if I'm being honest I was drawn to it because of the colour but it ended up being one of my favourites due to the unexpected spin potential and soft feel. Tension maintenance was pretty average but I string pretty often so not overly concerned about that department.
I didn't really find any extra spin from Poly Tour Spin compared to Pro (however it still is very spin-friendly), it was definitely stiffer and the severe shape on it really fluffs up balls (annoyingly)! However as the name suggests the two versions are reasonably similar, only obvious difference I saw was the stiffness. A good string but feel like BC has it covered pretty well in overall performance, I find BC more powerful and just feels better to me. PTS gets the thumbs up in terms of spin.