Having been a nursery manager, and now childminder, I have seen how wonderful both environments are when managed the right way. I left the nursery, despite it being an outstanding nursery, because I couldn't put up with office gossip and politics. A couple of the parents left with me and I now childmind their children.
Things for you to bear in mind;
Nurseries
-high turn over of staff
-if staff member sick, your child may be with someone new
- won't be able to go out to the park/farm/shops that often
-limited flexibility when children are sick
Childminders
-if childminder sick can be hard to find emergency cover (I have CM friend as back up)
-what will you do when CM is on holiday? Your CM seems to run a fairly small operation, so this may be quite easy for you to arrange amongst yourselves
-what's her sick policy say?
Overall, for me, the quality of care I provide as a CM is ten times better than when I was at the nursery. My care is very child-led, as much as nurseries say they do that, they only do within reason. For example, I may plan to do some baking in the morning, but a child may come in with a magnifying glass they got at the weekend, so instead we take buckets to the park and search for mini beasts (that happened this morning). A nursery would never ever have the resources to do that!
Also for a pre 24month old, there is so much value being in the home environment. It isn't loud, and noisy, and artificial. In my 8yrs in childcare, I've never known and cared for children in the same way that I have looking after my mindees now.