work/life balance is somewhat company and geography specific, but not much. The type of consulting project and especially the client / manager are most important. Here are some rule of thumbs:
1. Asia (esp. China, Korea) have the worst work/life balance
2. Due Diligence & M&A projects have the worst work/life balance
3. No single type of project will systematically offer an easy work/life balance
Company wise, they all have to balance working you to death and keeping you from resigning. Every company will brag about their great work life balance, don't necessarily fall for it. Ultimately, it shouldn't matter too much though: the more you work, the more you learn.
My recommendation is going into consulting with the mindset that work/life balance will be bad. On projects that have a good WLB, you will just be pleasantly surprised.