I like auctions for many of the reason that others have/will state. I would say that if you or a couple memebers of your league have a low BS tolerance, it won't be as much fun as some of the others will state. There is a lot more "gamemanship" in most autions that everyone has to learn their way through. For me. auctions are like going to a casino versus your regular corner bar. More exciting, more BS, and more chances of losing badly if you don't know what you are doing. I have been assuming live auctions, since online auctions are some other animal.
Live vs. online its all about knowing relative value ...Live auctions just have more spaz factor with less time to gather yourself and consider your bids ...You get a lot of snickers and crap during live auctions ... ETA: Worse, maybe much worse, than live drafts ...There is nothing like bidding up a player you dont really want to make someone overpay, or the flip side of that being hung out to dry thinking another bid is coming and you are stuck with the player ...

And before anyone says that crap is not acceptable during an auction ... it happens in every single auction.