vinyl would not be a good substrate, as it heats up, the vinyl may stick to the bottom of the tank, and it would provide crevices where bacteria and parisites may be harbored.
another thing to consider is that vinyl tyle is not intended to be exposed constantly to heat, it may release potentially dangerous gasses as it heats up. if i am not mistaken the vinly chains contain chlorine, which on heating may be released with hydrocarbons.
there are plenty of better options out there, if you are looking for easy to clean, i use low shag indoor/outdoor carpet, it cleans and disinfects easily and it drys out fairly rapidly.(it is exactly the same thing as the zoomed carpets sold in petshops) and your local home renovation store usually has end of rolls on special
aspen bedding, also works very well, and is easy to clean.