Amtico is the best. they then created the Spacia range to compete with Karndeans products
Karndean now have a few different products from the cheap Knight tile up to the better Renoir and Michelangelo
in terms of tile construction we need to look at the wear surface of the tiles .
Amtico has a wear surface 1mm thick over the photo that is the pattern and then the backing .
Spacia is about half a mm wear surface .
Karndean Knight tile is as thick as a sheet of paper. and easily pealed off with a finger nail.
the better more expensive karndean has thicker wear surfaces but none as thick as the Amtico .
fitting the subfloor preparation is the same for all the products above and the fitting techniques are the Same so any saving can really only come from using a cheaper tile or cutting corners in the sub floor.
Minimum ply wood thickness is 6 mm to over lay a timber floor but some will still use 3 mm
i prefer to use 9 mm over floorboards and 6 mm ply over Chipboard flooring.