As far as I know Sterling Kayaks make one of the best sea kayaks, its composite and it in USA. Other ones i know are in Europe.

The best is to have both, skeg and rudder. the biggest mistake people make is that they use rudder always and forget that you should learn to rudder you boat with paddle strokes and body. There is more to it but I cut it short.

You shouldnt forget that rudder can stop working or it may hurt someone during rescue, as its construction is sharp.

On waves, rudder may not be effective as it may happen to be in the air on a surf, hence skeg is needed.

Skeg is not so good in strong winds because it is hard to direct boat and lots of energy is used just for that.