I have the S&T no.4 mk1. Points to note:
The bodywork is quite nice - I’ve not felt a compelling urge to refinish/stain the wood (but I probably will at some point for the fun of it)
Mine had a horrible bolt pull at first (they all have this) - easily rectified with a bit of good lube, an aliexpress thrust bearing on the spring guide, and a cut down L96 spring (M130 or M150 flavours depending on whether you want a MED or not).
The back of my bolt was wobbly out of the box (a two minute fix)
Out of the box, the trigger box on mine wasn't attached to the receiver -at all. all four screws were entirely missing! But these things are super easy to take apart and it was quick to sort - plenty of video guides about
They use a bb feed ramp+ a loading plate/fin on the cylinder to guide a bb from the magazine. It seems luck of the draw from what I can read, but the C clip holding my loading fin on keeps popping off. The accepted mod is to make (or buy) a C clip made from an AEG brass barrel, and optionally fit an airsoft pro metal feeding fin intended for the TM L96 AWS, and slightly filed down to fit.
The both the front and rear sights are non adjustable (unless you count the rear flip up 'volley sight' as 'adjustable' - but that is not a problem really
They take VSR cut barrels and VSR/GBB hop rubbers
The range and accuracy is outstanding, even if you run it at 1.1j
In summary - lovely rifle, but unless you get super lucky, be prepared to spend a few hours doing some (easy) work to it in order to get it perfectly ready for a skirmish.
The jury is out as to whether the Vector Optics No.4 scope mount will fit it - I suspect that it would though - which together with the readily available stock cheek pieces would allow for a passable No.4 T sniper version to be created.