I've had some cool experiences on LIVE this generation- doing some of the Halo games on Legendary (Thanks to Spartan1Project for help with 3 and ODST), Borderlands 2 (still playing) some of the contracts I've played it Hitman... I'd say it's been worth it, and DLC's gotten a lot better since the start.
For next-gen? It depends on how many 360 games will be backwards compatible. If I can keep playing what I'm playing now, why fix what ain't broke? If not, I'll probably move to PS4, if only for Ratchet & Clank, Sly Cooper and the Assassin's Creed missions that have been exclusive to the console.
And Skyrim's DLC should finally work on PS3 by the time the PS4 comes out *Pointless take that followed by people ripping me a new one verbally*