Heliopan 100%
.....absolutely no comparison to Hoya as it is far better quality made of brass and with very handy numbers so you know where the polarising effect is.
.....also had a B&W slim one which went back to Amazon as it was so fiddly to use.
Oh, and if you get a 77mm one you can use it with most lenses with a step up ring, saves buying all different size filters!
Heather