Oh, it's worth it.
The system is still getting new games; quite recently I purchased MGSV: The Phantom Pain for it (you mentioned liking the MGS series). I'm going to get Persona 5 when it comes out as well. There are sales on the PSN all the time for classics and things, so you can find something fun regardless of budget.
To be quite honest, given the quality and titles on the PS3 at this point, I've had no urge whatsoever to buy a PS4. I may end up skipping the entire generation (well, there's the Wii U, but that's kinda still back in the PS3 gen IMO). But certainly I haven't seen anything at all on X1 or PS4 that makes me go "Ooh, shiny".