These are just my thoughts. One of the painful things is that you have to decide yourself right?
FOR ME, safety trumps most other things. If I felt both environments were equally good, the safer one would always win for me. I think this is because I have lost a child (not in a safety situation) and that's just my bottom line all the time.
(Not abuse, of course, or an environment totally at odds with my son's personality. So let's just assume that each environment has caregivers that are fine.)
However, the two examples you gave are not necessarily dealbreakers for me. Balloons can be unsafe, but I think supervised they are okay. (Not great. Okay.) Wading pools concern me quite a bit especially when the lungs are so small, but again, the critical piece is 100% supervision.
I've said on the forum that for me, safety-wise the home daycare (and there are great ones, I am just talking about my personal path about it) was the nightmare for me because I have to trust one fallible human being to be 'on' all the time, plus
the space is multi-purpose where a daycare is generally (not always) designed for the purpose of daytime children activities only.
In evaluating the centre I would look at staff hiring and training, turnover, and education, as well as physical space, ratios, procedures, philosophy, and food.
As far as education goes... despite having my son in a Montessori we love, I pretty much believe that if there are toys, caring adults, and other kids (or even not) that a child's educational needs can be met pretty much anywhere. That would not be a big deal to me before the age of maybe 4.