Pros
Unique experiences whether it is with colleagues or clients; won't find it elsewhere except the competition. Management is getting better and is certainly turning things around for the better, from most perspectives. Long legacy, a lot of history behind it, and you'll always have a good story for a dinner party.
Cons
Stuck in some old ways (but perhaps new management will finally bring Sotheby's to 2016? And hopefully soon?). A lot of work is done manually, so a lot of unnecessary over time happens. Not everyone that works there understands how the business works, or even how their whole team functions, people get wrapped into their own bubble instead of seeing what is best for the whole company or client. Last, but certainly not least, pay is so incredibly low and they (in certain departments) unfortunately drag their Floaters through a lot and never hire them, when they would instead save time and resources to just hire them instead of getting a new floater and going through training them again. You're better off getting an entry level job elsewhere, then coming to Sotheby's and asking for a bigger number.