RCP is about 4 miles from City centre off rathoath road. It is in what was apparently the last undeveloped green area within the M50 when it was rezoned back in the late 90's (according to newspaper reports at the time). It borders, Ashtown, Navan Road, Finglas and Cabra (although is being marketed as Castleknock!!). Location is good, can be in the city centre in 15 mins, although this can also be 40 mins (you just never know). There is currently a train running past RCP (the much maligned Maynooth Express, possibly more akin to a sardine can than a train by all accounts), this takes about 15 mins to get to Tara St and RCP is maybe 7/8 min walk from the station? Developers are Ballymore.
There are numerous large shops relatively close - Tesco clearwater or Stoneybatter are reasonably equidistant from the development, Blanch is only about 15 mins in the evening (8 hrs on a saturday).
As for appreciation, I would favour location over size in apartments, but 688 is pretty small for a 2 bed not in the city centre I would think? You pays your money