We have done it both ways. ONe holiday we took my parents too, DD was 9 months then and to be honest it was really hard work. She just didn't want anyone else but me, period. She also wouldn't drink any milk and barely ate anything all week!
When she was around 18 months we went with esprit and she was in their nursery. She was fine, cried at drop-off but it stopped as soon as we were out the door. Their childcare is really excellent, I couldn't fault it at all.
We're going again with our (now) two children in MArch and both will be in childcare for half the day. The other half we'll spend with them. For us that's a good compromise. We're also taking my mother in law, mostly so she can have a break but also so that if DD doesn't like the childcare or something, we have a bit more flexibility.
Esprit were really good in that you could call up the nannies and see how your baby was doing - also, you don't have to put t hem in for hte whole day. You could do, for example, 2 hours in, then lunch together, then 2 hours in again. There are other similar companies, ski famille looks good on paper but we haven't been with them.