Pros
I can share my perspectives with respect to product dev org in Oracle India. Donno much about other orgs(some 20 are there...product dev consists of just 1 or 2)There are diverse products/technologies available to work in. They were not really built by oracle but nonetheless it owns it and they all have been best of breed. Lots of developmental/design efforts are continuously going on, which keeps you learning all the time. And that means learning real good stuffs. I work as product dev engineer in Siebel and the work is nice. Compensation is pretty decent. Nobody minds the hours you work at your conveience (you have to work pretty long hours though) , the result is what counts(you have to explain ofcourse in case you take longer than expected..no free lunch there). Overall, I would certainly recommend joining oracle.
Cons
Long hours. IT infrastructure is not very good in Siebel prod dev..not sure about other groups. Somehow, it is recruiting a lot of very avg. engineersfrom private unknown institutions just to ramp up the operations fast, which is not a good thing.