I've been reading this thread with interest. Isn't childcare a minefield? The suggestion on this and other threads is that grandparent day care is substandard and will be a day filled with TV, sugar and no interaction with others!
I'm a Grandmother and I'd like to share my experiences of childcare. I'm currently looking after my 11 month old granddaughter one day a week. Her other grandmother has her one day and the remaining two days she is at nursery. The generalisation that Grandparents are past it, opt for an easy day by pacifying the GC with sugar and TV, don't listen to their children re their way of parenting is insulting. Our Granddaughter is taken care of very well when she's in our care. We follow her parent's way of parenting. She is loved and cared for very well. We talk, read and sing to her, take her to the park, baby groups, cafes etc but if she just wants to relax and explore her toys at home then that's ok too. We all need down time! This is the same level of care my friends also provide for their grandchildren.
Regarding the comments on illness; in my experience so far, nursery often send babies home when they feel they're coming down with something. Sometimes my daughter and son-in-law choose not to send the baby to nursery as she's over tired etc so she'll come to one of her Grandmothers. This is far more often than a Grandparent being "unreliable" due to sickness. Grandparent day care is much more flexible!
Communication is key to Grandparent childcare being successful. If you don't like how something is going then please speak up for the sake of the child! I really do not take offence to my daughter asking me to do something a particular way. I know she loves her DD and is just being a great Mum.
Our Granddaughter will be going to nursery 4 days a week when she reaches the age where socialisation will benefit her. So around 2/2.5. At the moment nursery is providing care just as we are. They're doing a good job too.
So, in summary, if you are lucky enough to have willing and able grandparents offering childcare, please take it especially when the baby is young. The bond between grandchildren and grandparents is so special. I totally accept that Nursery would be a good choice when the child is wanting/needed to be with their peers.