Pros
Perks as a sales rep, laptop, expensive dinners with customers, rental cars, flights, hotels, box seats to sporting events with customers, phone and internet bill all expensable with corporate card. Working from home is great too, you could work from Jamaica, and no one would know. The IBM brand name is great too, you will never be denied a meeting because you represent IBM. The conferences are top notch and are done at the best hotels, celebrity keynote speakers, and if you have customers, you get to spoil them and yourself all week long with expensive dinners even bottle service at the best clubs in Vegas (if your manager approves).
Cons
Huge quotas, internal politics, red tape, conference calls, constant fear of layoffs, backstabbing when things go wrong, the amount of internal administrative crap you have to do that takes away from your productivity, cadence calls, etc. If you have a crappy manager, your life will suck at IBM as a sales rep...period. Getting taken off of accounts in the middle of the year, or at the beginning of the year is frustrating as a sales rep b/c this is supposed to be a relationship business. When you're best friends with a CIO, and you have millions of dollars coming your way for years spread out over 4 quarters, it's hard to see that account go to someone else due to restructuring.