Night Angel is very good but the third book feels repetitive and the main character is very whiny. Havent read the other series but heard its better. Night Angel trilogy is complete, Lightbringer isnt.
I don't think it's fair to call anyone the poor man's someone. Brent Weeks is a really good writer, and Lightbringer has a very cool magic system and plot. And there can be as many guys out there trying to emulate Sanderson because I love the non-grim fantasy with unique and exciting magic systems.
I like Brent's work a lot. To me, he's on a level with other contemporary authors like Scott Lynch and Peter Brett. As for style, hmm, difficult. Night Angel comparable maybe to Jay Kristoff's Stormdancer? Lightbringer is a bit different, more Sanderson in terms of magic system and characters. Lightbringer is a little, um, lighter and the magic system is more complex.