Vantaggi
A lot of opportunity for growth- they will let you take on whatever you think you can do (until you fail). Interesting subject matter, constant change, 'the next thing is right around the corner'. Ability to travel (though it can become a bit much- be careful what you ask for).
Svantaggi
SE culture. Everyone else is a doormat (in a lot of the local practices). Finding a good SE to work for is like panning for gold. Time in role as a basis for promotion. Completely arbitrary. Work Life balance is a shambles. You may put in 12 hour days, but pressure from the project limits you to 8 hours chargeable which means you cannot catch up on your chargeability targets on the next project. Once behind, you are in the death spiral. Insular culture- each project is a mini-world. You are seen as a traitor is you want to work on something else/communicate to superiors about the project (even if parroting the project line)/or report outside the project management structure (i.e. matrix org).