What's the motivation to get this on next gen rather than just playing on Xbox 360? Not sure I want to take the plunge for just one game unless you guys can convince me why I should.
If you are still on the fence, I wouldn't make the jump. Late 2014 (Sept-Dec) there will be quite a few games coming out that might be worth it for you. Destiny is just one of those.
Some will be next gen exclusive, such as Dying Light (zombie game akin to Dead Island), some will be cross gen such as COD.
The only thing I can say that might convince you for a game such as Destiny, to upgrade, would be that there is a very good chance there will be more players playing Destiny next gen than ps360.
There is likely close to 13 million of the consoles out there, the more dedicated game players already have them, and will not be buying games for the old consoles. All of the recent releases, TF, Watch Dogs, etc have sold better on next gen. A lot better. PS4 had 50% of the Watch dogs user base, for example. That number will only grow, and by the time Destiny comes out, it will very likely be over 50%.
But again, that is the only reason you should upgrade if you aren't particularly looking to. For an online based game, user base is a big part of it.
Edit: Just to add, ps360 is dying. I would expect that all the next wave of games will be ps4/xb1 only games anyways. Software sales have just fallen off a cliff for the old gen, so there is not much motivation for the companies to make games for the old consoles.