I haven't played Crimson Dragon yet, but I have Halo on XB1 and WP8. Having said that, I would recommend Crimson Dragon. Halo is pretty shallow, and its kind of annoying the way they just copy pasted it from WP to XB1. Microtransactions in this game are unnecessary and should have been removed for some other unlock method. I would say wait til it goes on sale to buy it, it plays decently enough but its all to apparent its a WP port which doesn't really get me pumped to play on my $500 XB1.
I own both and wouldn't recommend either of them. Crimson Dragon is a 5/10 game, and Spartan Assault is a 6/10 at best, and I think the only reason I give it an extra point is because I'm a fan of the series. --- XBL/PSN: LinkRemembered 3DS FC: 2621-2606-4343