Pros
I've been here over 12 years and have had the opportunity to build all kinds of elaborate systems that changed the company. The early days were quite demanding, but the satisfaction was immense. I'm still challenged, but at a sustainable rate. The growth curve is like few other places. I interviewed an old mentor from HP 5 years after I'd left. I felt he'd atrophied, but the real deal is I'd grown tremendously. Most jobs (I'm sure there are exceptions) use strong, current technologies. We clear the table and rub two sticks together to make a fire. As the smoke starts to generate, we may notice we've moved a pack of matches- but alas, we know this fire and where the hot spot is. Keep rubbing the sticks together. This is also a competitive advantage, tight integration w/ every other piece of the system.
Kontras
It's clearly not for everyone. If you want tenure based promotions, silo org'ed structures, find a job somewhere else, and count the days to retirement. There is a bit of a libertarian angle on many decisions which doesn't bother me. It is getting very large.