Pros
Allegro has some very smart people and there are a few good managers. The product is great to work with, highly extensible, and highly regarded in the industry. The culture is friendly and non-competitive. Most anyone will help you if you ask. There are many recognized holidays and they give plenty of vacation. Once you've proven yourself to be valuable, they will reward you with a nice salary and bonuses. The yearly company holiday party is always a lot of fun.
Cons
The downside to this place is that interdepartmental communication has never been good or even mediocre. It's been horrible. There is a certain managerial level that you don't want to get promoted to or beyond because working there will stop being rewarding and start being unnecessarily hard. Product documentation and training continue lack much real value. This company relies heavily on people who have been there a while and know what they are doing to "save the day" on projects.