Vantaggi
SLB is a great place for an engineer to quickly gain experience in the oilfield and obtain a yearly salary + bonus that matches that experience. The fixed step program is focused on quickly making new hires competent. It's also great if you want to travel a lot (and express the willingness to do so).
Svantaggi
SLB has the same problems BP is now plagued by. Too much focus on documenting and globalizing every single process. There's a global focus on the "Transformation", which is corporate code for taking autonomy away from local decision makers and pushing it further up the food chain to decision makers in Houston (headquarters). It makes you feel helpless. A secondary problem for me is questionable local management, but this will obviously vary from person to person and location to location.