What is like working in an asset manager that mostly executes on PE secondaries and co-investments and little direct investment?

Experience:  much more of a "portfolio management" type experience - you aren't going to be getting into the weeds like a direct GP seat (ie. analyzing operating data, weighing in on strategy/operations) and you won't have access to mgmt. teams. Much higher level view of PE as an asset class that you don't really get exposure to below the partner level at a GP (fees, legal structures, funding mechanisms, etc.).  Analyzing GP track record is a large part as you're not in the driver seat in either secondaries or co-invests. 

Career progression:  can be a bit slower but really shop dependent.  For a large LP, slower as these are fairly cushy jobs with little turnover.  Big alt. asset managers that are more aggressive probably see faster progression (maybe more turnover though). 

Comp:  discount to the direct GP side on a like-for-like basis (can't really compare Coller Capital to a sleepy LMM shop) but at the benefit of (usually) better hours. Co-invest is typically less work but still deal-based so hours can approach "PE-light" depending on activity. Carry component will vary from firm to firm (basically none if you're at a pension fund) but expect some discount to GPs in terms of carry $. 

Exit:  Narrower imo. That's because toolkit is narrower (no direct portco experience, not leading deals), but many view these asset manager seats as the exit themselves given generally better hours, more stability, and less travel.