Pros
If you are young and just out of college, it's a good place to start. But the raises given to employees after five years are puny (2-3%) and without getting a promotion there is little chance for increasing your pay. In other words, the longer that you are employed the less you are appreciated. In all fairness, Thomson and Reuters have just merged, so there is hope for some change, although the previous acquisitions and mergers have not shown many changes.
Cons
After you have been working there for more than about 5 years, you have no opportunity for advancement. Not enough levels within job categories. The long term employees are hold-overs from West Publishing, a lot of whom have never worked for other companies and have been willing to put up with treatment and policies in the past that would not be tolerated by newer employees. But with retirement coming up, they are willing to put up with being shuttled to "trained monkey" type work, while newer employees are given training in newer systems long before proving they understand the processes. Long term employees are expected to clean up messes left by them.