This seems to be the general sentiment I'm seeing.

As a multiplayer game, yeah, it can be fun. Not the best, but better.

In the context of Halo? Nope. Maybe some trailing remnants of what was Halo, changed with claim that Halo 'must evolve'... but it's not really the Halo that made Halo great.

I have access to the beta but haven't actually played it yet (for shame) due to lack of time over the holiday, but the thing I still latch on to as one of the core "Halo" things was, as Gravemind put it:
"It lacks the "feel" of Halo. The gameplay is just too fast-paced with everybody darting around"
There's just a certain something that makes the 4/5 Halos not really 'feel' like Halo. Evolution of the franchise is not a bad thing of course, it needs to be done, but I think the evolution is happening perhaps in the wrong areas. =/