I think Belarmine represents the best value you can get on the southside at the moment. As for the neighbourhood - it is a mix of people from the very wealthy, to young professionals/young families, to those in rented private or council owned properties. Take a walk through the development in the afternoon and you'll pass people out running, walking dogs, couples with babies, children playing in the playground etc. People tend to say hello to each other a lot while out walking which is something kind of rare in many developments now. There's a nice feeling of it being a real neighbourhood, not just anonymous apt blocks. Many people rent or buy small properties there initally and then want to remain in the area when they move up the property ladder, I think this is a very good sign.
Prices are low now because the builders want to get rid of recently built apts before prices fall any further. When the remaining units are sold I think prices for resale will compare favourably with other areas where you can currently buy at the same price.
As for walking there at night time; I would say it is safer than anywhere else you could buy at the same price. Personally I bought there because I wanted to be able to go for walks alone in the evening and didn't want to worry about anti-social behaviour. There are lovely green areas with streams and nice mature trees for walking around. Take the same care you would walking anywhere late at night. It's not as exclusive as somewhere like foxrock, but much safer than places like the docklands, city centre, blanchardstown, santry, tallaght, areas of lucan etc.
The 47 bus would be outside your door and would take you as far as stillorgan/donnybrook. 44 goes through the village and goes from Enniskerry to city centre. There are other buses too from lambs cross and I think one of these goes to Blackrock. Luas will be within short walk next year.
The halting site has been delayed and people are still objecting to it. Looks like it mightn't ever get the go ahead. If it does go ahead it is a four unit site only which is isn't big and it's not the same site as Belarmine. Would have a separate entrance down the road.
The presence of affordable housing won't effect anyone buying at current prices. I bought under affordable housing and paid more than you will pay for your place now - so I couldn't undercut you when it comes to selling. The people who are negatively effected by affordable housing are those who bought 2 beds for 450k - and they are more effected by you buying for even lower prices now. What's more those who bought on affordable are all young educated professional owner occupiers - much better than having investors renting out beside you. Bulk of affordable units will most likely sell now on the open market privately as prices have fallen and govt has given the go ahead to sell them to the general public.
As for parking, it depends on the particular development. I have an allocated parking space.