I've worked in nurseries for almost 20 years and they are all very very different. Some really are terrible, and others are lovely nurturing places where children thrive.
The quality of a setting can easily vary & change over time to depending on staff turnover, group size, ratios, qualification/experience of staff funding, effective management (or not) , individual children, parent community, how genuinely inclusive the centre is etc... If any one of these factors is an issue it can often be balanced out if the other areas are strong.
I would try and avoid large group care and long hours for a very young child if it is at all possible, but if you do not have an option try and aim for:
Small group size (ideally under 15 children)
good ratios (ideally 1:3 or 1:4 max)
Qualified & experienced staff, with low staff turnover
What professional development opportunities do they have?
Visit the setting- are staff at child's level (sitting with them, chatting with them) Is there a busy, happy, 'buzz'. Do the staff & children look engaged & happy?
Do the children seem to have a good range of experiences to choose from independently? Do they have access to outside, to run, make noise, make mess & play freely?
Do they operate a primary caregiving/key worker system where one main person will help settle your child in, get to know them & keep an eye out for them?
These are all good quality indicators.
I also like to look at the art of the walls- Is it all pre cut copies of the same thing (adult directed) or are there individual examples of different work (child led) . This may indicate that they foster & value individual children's efforts, ideas & creativity and understand best practice vs just worried about 'sticking any old thing up' or displaying parenting pleasing 'products'. Not a perfect sign, but a good start & hasn't failed me yet ;)