No, I've not completed Destiny. But I have bought a copy and I watched Number One Son get to the closing stages when he came to see us. I'm still fighting way back at the start of the game, standing around admiring the scenery and getting shot in the head.
I like playing it. Just like I liked playing Halo. In fact, if you'd sat me in front of it a while back I'd have thought it was Halo. Even the way that the music kicks in is very reminiscent of the Master Chief.
It will be interesting to see how the multi-player aspects go. The game is gorgeous to look at (although not really fourth generation enough for me - it looks a bit PS3/XBOX 360 in places) and if you liked Halo I reckon you'll love it.
If you are looking for something that will change the face of entertainment and provide the next level in massive multiplayer gaming I reckon you might have to wait a while. But you never know, the studio and the publisher are in this for the long haul and they now have the sales to back it up.