Hi there, I'm in the same boat put a deposit on a 4 bed and not from Ashbourne.
By all accounts the finish on the houses is superb, that's going on structural engineer reports from other residents. It seems the 3,4 & 5 beds your getting more for your money in Churchfields however maybe I'm being an over enthusiastic buyer. I think with more of us buying and moving to the area more shops on the shopping street will open, I see a specsavers opening in October.
As you mentioned the big pull are the five supermarkets and the ability to walk to them if required. Roughly an 8 minute walk to the Ashbourne Connect which appears to be a reliable quick route into town which is important. The 109A gets you to the airport while the 103 is another bus to Dublin but unsure how reliable it is.
You can see Cairn put a big effort in getting the first part of the estate nice & pretty by the showhouses with the little green area/park so hopefully the rest of the estate will be like that too.