Pros:

Have some adult time
Get my brain ticking again, on things other than child related stuff
Extra money

Cons:

Travel
Less time to spend with DD
Less time doing home stuff (cramming it into less days)

DD was 10 months old, initially looked after by DH four days per week then I eventually went part-time and am now doing a 5 days fortnight.

DD is in creche 2 days per week and every second Friday, my mum looks after her. In the early days DD was looked after by DH & myself, with me being the main carer.

Mummy guilt - DD is 4 yo & I still have it from time to time, depending on how my home/work life is suffering or is in a good place.