Pros
Without out question Slalom attracts some truly awesome people. Transparency - Slalom genuinely works to be transparent with its team members, even when the message isn't positive. Career management and people management - for the most part, Slalom takes these activities more seriously than any professional services organization I have worked for.
Cons
Although not alone, Slalom has struggled a bit to adapt to a changing consulting landscape - this adaptability muscle needs further attention and strengthening. Professional and compensation growth is generally good for the first 2 to 3 years, but beyond this it can be a bit hit or miss. Not always clear that structure and org changes are as much performance/outcome driven vs. rewarding/retaining team members that have the right connections/relationships. Not unique to Slalom, but something they might strive to address.