I have to say that, growing up, I was never much of a fan of Namor. But the launch of this series changed all that.
Writer/artist John Byrne does what any good creator should do with a character with as much history as Namor. He hits the high points you need to know, while setting up the direction things will be taking from this point on. He cleverly addresses Namor's conflicting attitudes with the surface world and begins to build a very solid foundation for all that is to come.
Artwise, Byrne was at the top of his form here, giving Namor a power and grace of royalty, while never forgetting that he is also a warrior. While Byrne's skills would begin to falter as the 90's progressed, his execution here is exactly what you'd expect of someone of his reputation and skill.
All in all, this is probably as close to a perfect first issue and anything you could hope to find in this era. A true standout in a very great period of comics storytelling!