Pros
The software development cycle is very mentally stimulating, and successes are always celebrated. Working close to the cutting edge in many parts of the company. Coworkers are honest, friendly and highly skilled. Great support for employees (salary, benefits, training), especially for those at the beginning of their career. Overall impression that everyone, from your coworkers to your line manager to the company as a whole, cares about you and your career.
Cons
Need to make a proactive effort to understand the existing systems, especially at first. Can be somewhat difficult to get ideas propagated throughout the organisation. Some bumps in the road related to organisational changes.