I've only used 'cheapies' from Big W and Myer and all have been great. They're made out of t-shirt material and the Myer ones were 0.5 tog rated. We also had a couple of Pumpkin Patch ones...think they were tog rated (0.5/1.0 from memory). One was fine but the other had all the press studs fray/break off within a few weeks. DS used sleeping bags from about 6months to 2.5 years.

Can't help with the daycare qu though as he only ever wore them at night.