Pros
Work is full and straight-forward. Infrastructure that has been built makes it easy to extend, without even modifying objects. This is the single biggest reason work was so satisfying - instead of an insane cycle of fixing bugs, the (positive) energy was spent building on top of the known-good code foundation! A Computer Science course about simple, clean code, with lots of space to extend should really have LSBio's environment as the gold standard!
Cons
It is a small company, so Software Engineers also tended to be IT support staff too. It's not so much a "con" as it is a reality in a small company - you won't be "stuffed away writing code all day". If a printer is broken, you'll definitely be called to help. Router needs to be moved? New disk array needs to be installed - by all means -- save your work and get up and get your hands dirty -- AND be happy about it!