Good is what fulfills your requirements. Have you defined this? Whether you want to pay the respective price is a different question. You can have a look at the price list for filters here in the forum.
I always recommend Nikon polarisers simply because they are much more efficiently as far as light loss is concerned. With Hoyas and the likes, I typically loose around 1.5 to 2 stops. With Nikons, its only around 1/3 to 1/2 a stop.
Some camera manufacturers (and pros) have suggested using center weighted or spot metering on your camera. My CPLs work fine with matrix metering. I tend to use Aperature Priority mode and leave the shutter speed to auto compensate. Works fine for all my photos so far.
You can always try directing your questions by email to the following filters retailer at :-
Do I have to keep switching filters? Meaning CPL only for shots with sky or water. Then, if I shoot portraits, people, flowers, etc... I need to change back to my UV filter?
It's quite troublesome. Had this problem at Sentosa flower event. Not all pics had sky or water and I kept thinking if I should remove the filter.
First you could dump your UV filters, quite useless (imho). Your camera doesn't need any UV protection (lenses filter already, the sensor has a filter, too) and for protection a lens hood serves better. If you insist on UV for your peace of mind then you need to change. Otherwise (meaning you stack CPL on top of UV) you might get vignetting (dark corners in the picture).
First: get clear about what you want to shoot. No point jumping between beach and flowers and screwing filters on and off. Stick to one object / scenery. Secondly: filters have a purpose and effect. If you intend to use this effect then put on the filter, if not then just don't do. Filters are an optional element for certain conditions, they are not compulsory in general.
Scroll down, in the Nikon posting there's a 77mm CPL II (IIRC, that's the slim version). The prices are still somewhat valid. Compare with the MO threads and you'll see that 77mm B+W still goes for about SGD 110. Check here. (MO saves the few bucks that go for shop rental and aircon.)