I have a 360, but I'm really temped to jump back to the PS4 next gen because of Microsoft's greed in charging for most services on Xbox Live. An always online requirement would guarantee me making the switch.
I don't mind Microsoft charging (PS3 doesn't, but PS3's offering is missing features too) for online play. Always on... might be a deal breaker, or at least a deal delayer.
I'm not going to jump to the PS4 instead, though. Their interesting exclusives (mainly Uncharted
and a bunch of PS2 rereleases) aren't enough to justify launch price for a console.