Pros
People are old, which means younger employees are much smarter and can easily get away with alot. Overall the people are very nice and share alot of information. Training is also very good as the bank dosen't really expect you to know much, if you do alot that that's great, if you don't no worries they will train you.
Cons
I worked there for 3 years. I can honestly say that it all depends on the type of job grade you start at. If you start at a grade 30 there are not many jobs out there for you when you want to move up from within. My suggestion is to ANYONE who is interviewing at BMO is ask them what the job grade is. All the good jobs start at grade 32 and up. If anything starts under that don't take it as it will kill your career. After working there for 3 years I have to pretty much start at the bottom of the IT ladder because thier systems and processes are outdated. Don't fall into the same trap. Go to a smaller company for less money but knowing you will learn more and grow faster. Then come to BMO with good experience, this will ensure you don't get a low job grade to start.