B+W and Heliopan multicoated filters are the best you can buy, but polyester and C32 resin filters aren't bad, and the Gel Snap system is attractive if you use classic lenses with odd filter sizes, and if you want to use ND grads, you'll need a resin filter system (even the Heliopan ND grads are resin filters, I believe, but in Heliopan's special holder). I don't know whether the Gel Snap system takes ND grads--I think it is just for gel and polyester filters, which are thinner. I have lots of 3x3" resin filters, mostly from the old Ambico system, as well as B+W and some Heliopan and Linhof, which are made I think by Heliopan.
Once I tested all my UV filters--even a cheap multicoated filter is better than a single or uncoated filter, but a resin filter is often better than an uncoated filter. Resin, polyester, and gel filters are of course more delicate than glass.
If you decide to go with glass filters--If you prefer a filter wallet, then go with B+W, because the filter type is engraved on the retaining ring, visible from the front of the filter. If you prefer to stack filters with stacking caps (which is more compact, but not as quick to use), then go with Heliopan, which have the filter type engraved on the ring in the normal way.