Do these sunglasses block UV rays?

Yes. The HG 1348/S is listed with UV protection, so the lenses filter ultraviolet light. That covers basic sun protection but does not mean the lenses are polarized.

Are the lenses polarized?

No polarization is listed for this model. If you need glare reduction for driving or water, look for a frame explicitly sold as polarized.

What face shape suits a rectangular frame?

Rectangular frames tend to balance round and oval faces by adding angles. Square faces can also wear them, but very narrow faces may find the width too much.

Is this a men's or unisex frame?

HUGO lists the HG 1348/S as a men's style. The rectangular full-rim design is fairly neutral, so it can work for anyone who likes the shape.

How does it compare with sport sunglasses?

It is a fashion frame, not a performance one. Sport models usually add polarized lenses, grippy nose pads and lighter materials; the HUGO focuses on looks and branding.