That is where this is confusing though, kidderek. S+T is part of an Investment Bank. IB is a conceivable phrase for Investment Bank, or - as the acronym seems most commonly used - Mergers & Acquisitions, Corporate Finance etc. It is easily confused.
I think that getting the idea that S+T is the easy life in comparison is erroneous (not that I am saying anyone is making that mix up). Taking into account the level of pressure, S+T is often a hell of a lot more stressful, because you are constantly on the line against data, living with the flow you have, whatever. If you don't have a position, you won't make money, so normally - you have risk to worry about.
M&A is all about exhaustion. S+T is all about stress. People I know who trade work 7-6 (reasonably high up), spend time with brokers, and often go home and read text books to brush up on models and things they feel they need to know. To a certain extent it depends on what type of person you are as to how much work S+T is.