Sasa - the best thing would be to go along and have a look to see what the atmosphere is like. It differs a lot according to the local area policy. DS1 went to a state nursery, where there was no uniform, lots of freedom of choice about routine and play choices, virtually no schedule. i.e. for the first hour they were inside with free choice, for the second hour the doors were open and they could choose to play outside in the garden as well if they wanted.
DS2 went to a different state nursery class - there was a strict uniform, a very strict routine/schedule, a bit of choosing - but not much 'free choice', a lot of emphasis on behaviour, politeness, walking around school silently in single file, that sort of thing. A scheduled 30 min slot compulsory outside play. Also they did a lot of singing, PE, formal letter-learning, weekly library sessions, attending assemblies ... school sort of things. DS1 did none of these.
IME the less mature children actually do better in the second sort of class, where the rules are clear and strict, and they don't have to make choices and value judgements about behaviour. In theory I like the first class, in practice it was a dreadful place for ds1, who was emotionally very immature at this age, but academically very bright.
In the end though both have done/are doing exceptionally well at school, so I'm not sure the choice of class is that crucial anyway. So if I were you I would go and have a look, see which appeals most to you, and also which is practically most convenient for you too - location, timing of sessions, etc. Will he be at this nursery for 5 terms? Some playgroups allow older children to do a full day and stay for lunch, which is usually not possible at state nursery classes, and this may be helpful.
HTH