First, I have to say that THIS is the level of expertise I hope to someday - in the probably very distant future, most likely :P - have. My first reaction is stunned awe with a side helping of "OMGwow so pretty!". :D
Second, Harry's expression is a lovely, inspiring mix of contentment and wistfulness, and there's something about the set of his jaw that speaks stubbornness and challenge to me. :) And the cutest touch is the crooked glasses. (The artist in me wants to know how long the ear took to get right. :P)
Finally... This is quite possibly my favorite portrayal of Severus yet. Fics tend to describe him as "sharp-featured" or "stern" or "hawk-like", and let's not forget the favorite of "thin-lipped" :D, and I'm guilty of that too. But you've drawn him as hsving strong, but incredibly sensual, features. Reminiscent of Val Kilmer in his role as Madmartigan in Willow, just with a stronger nose. ;) His expression, to me, says "I'm here" with.. I don't know, an air of honest simplicity.
To put it more simply: it's absolutely gorgeous and touching and I love it. :)