They have good prices. That's about it for the pros.
Cons: ABYSMAL customer service. Terrible. The employees have two possible states: they can appear to be inconvenienced by your presence, or they can appear to outright hate your guts for trying to buy anything.
Orders are never fully fulfilled. Never, not once have they had everything in stock that their website says they do in five years of purchasing from them. Inventory control needs some help. Not the biggest deal, unless you're really counting on them to have what they say they have. Then you might be screwed.
We still buy from them because of the prices, but it is a horrible experience every time. The second we find a competitor that has similar prices Ryan's can kiss our thousands in purchases per year goodbye.