I think a lot depends on how many PS3 big releases you have played.
For me I missed Assassins Creed Black Flag, Rayman, Tomb Raider, FIFA (for several years), Need For Speed (missed the last few versions), The Last Of Us and Final Fantasy 14 on PS3 so there were several AAA titles that I wanted to play.
I gave up on PS3 just after purchasing GTA 5 and GT6 which were the big hitters I really wanted so when finished those bought my PS4.
For me with these titles and the free PS+ games (Resogun & Trine are my faves) there is plenty to play.
I have also bought Infamous (worth it just for the beauty of the game and photo mode) and Watchdogs (good fun game but not technically that impressive).
Here's a list to the current PS4 releases:
http://www.metacritic.com/browse/games/release-date/available/ps4/metascore
For me almost too much to play when you include the free to play games Warframe, War Thunder and DC Universe Online.
Then again I work full time so game maybe a couple of hours most evenings and weekends - if you have played all the best PS3 games and biggest recent releases then I would agree with the other posters here and say the most impressive games look like 2015 releases (Bloodborne, Batman, The Witcher 3).
It's difficult to say what you should do but have a look at the games and then decide for yourself.
I've not regretted my PS4 purchase for even a second - slick and fast to use, downloads automatically updates, Joypad is way better especially audio jack and boy when you get Neon in Infamous will you sit back and just think "Wow for £350 I get a game like this?!!!!!!".