Strengths are great positioning, technique, reading plays, and ideal size. Weaknesses: primarily concentration, but his rebound control isn't always great, and his reflexes aren't amazing (for a goalie) either. He's technically sound but has a virtually guaranteed concentration-lapse related goal (that I've deemed the "nightly blonde goal"). He'll play an otherwise solid game then just let one in that should have been an easy glove save or something like that, and he kicks rebounds out directly into the slot more often.
There's basically two types of goalies; reactionary and positional.
Reactionary tend to play the older stye "standup" or a "hybrid" style and rely primarily on getting into vaguely the right spot and then having incredibly fast reflexes and superior athleticism that allows them to throw out a leg or something to block a shot. They're also responsible for a lot of those highlight reel stacking the pads or flipping on their back types of saves, they do completely unconventional contortionist kinds of things to stop pucks. The two best examples of this style in the modern era are Dominik Hasek and more recently Tim Thomas. This playing style is virtually extinct since these kinds of goalies tend to be viewed as less consistent (for obvious reasons).
Positional or "butterfly" goalies rely on reading the play, getting into the proper spot, and keeping themselves square to the shooter, and basically just making the puck hit them rather than forcing them to actually do something extraneous to make a save. Martin Brodeur is the perfect example and probably the best goalie of all time (despite all the spectacular acrobatic saves he's made over time, notice that initially he's out high on his crease and square to the puck completely under control while Hasek was always low in his crease looking like he was flailing like a madman), but virtually every goalie in the game now is a "butterfly" netminder.
Just go to youtube and search for highlight videos of those guys and you'll get the idea. Crow is a pure butterfly goalie and his skills suit that just fine.
