This is Xbox Live's Games With Gold, Vs PlayStation's PS Plus EU, on which has given you the best FREE games in September 2013 on Xbox 360 & PS3.
As a note, PS Plus Vita games don't count as this is just Xbox 360 Vs PS3.
Ok we are going to look at the value, looking at all games and how much they would cost without the service of Gold and PS Plus as a download and as new on disc.
First lets go with Games with Gold,
Ok so in September 2013, Xbox Live Games With Gold gives you Magic 2013 and Rainbow Six Vegas.
PlayStation's PS Plus EU gives you, Assassin’s Creed 3, The Jak and Daxter Trilogy and Stealth Inc: A Clone In The Dark
First lets go with Games with Gold,
Magic 2013 will cost you £6.99
Rainbow Six Vegas Download cost is £11.99, but you can buy it on disc, New For £9.99 with free P&P, so we will use that one.
PlayStation Plus EU,
Assassin’s Creed 3, Download for this game is £11.99, disc best new price I could find at this time was £16.99, so we will use the £11.99 one.
Jak and Daxter Trilogy, Download is £19.99, disc best new price I found was £27.99, so we will use the £19.99 one.
Stealth Inc: A Clone In The Dark, Download is £7.99.
Results
Games with Gold, Saving you £19.98
PlayStation Plus EU, Saving you £39.97
As a note, this is just what I could find at the time, prices don't stay the same and may change at anytime, this is nothing more then looking around finding prices.