I've passed through PHX a lot this year, on my way to and from California. Although it is not at the top of my favorite airports list (Portland and Copenhagen take the cake), it isn't the worst place to make a connecting flight.
Some of the best elements are the free wireless, abundant moving walkways (if only people would abide the stand-to-the-right rule), and decent food options (for an airport). Some downsides are that it may take you a while to get to a different gate for your flight, which can be incredibly stressful if your first flight got in late and you're rushing.
Although the airport is busy, there are usually enough seats to go around, except for holiday travel. Unfortunately, I can't speak to TSA there, since I have never entered from the outside.