The Heliopan 77mm SH-PMC Slim Circular Polarizer is similar in quality to the B+W 77mm MRC Slim Circular Polarizer Filter - Excellent (read this review for more about slim CP filters).
Like the B+Ws, the Heliopan 77mm SH-PMC Slim Circular Polarizer is made from brass reduces binding. SH-PMC is Heliopan's multicoating - a very worthwhile feature in my opinion.
Unlike the Slim B+Ws, the Heliopan 77mm SH-PMC Slim Circular Polarizer is not currently shipping with a push-on lens cap. Be sure to order one of these accessories if you get this filter.