Pros:
Combat is amazing
Weight and Physics feel accurate
UI is elegant in its simplicity
Graphics are impressive with damage showing up exactly where and how you got hit
Maps are large and beautiful to look at
You can set the forests on fire (and you will... over and over again, because you can't bloody see through them, these trees are all like 150feet tall).
Cons:
Narrative is written by a 5th grader
Missions make no logical sense whatsoever (let's save the VIP, great, now let's fight a "rear guard" mission while the ship fuels, except... it's somehow on another planet... that took us 17 days to get to... wth?
You remember that Ultimate Follower Overhaul that kept followers from being idiot killjoys and getting you in trouble in Skyrim? Yes? This game needs that... The Ai FREQUENTLY walks through (thereby destroying) things you're supposed to defend.
Terrain, yes it's pretty, no you can't walk on most of it, you'll get stuck permanently if you jump jet into it, and boy oh boy the Ai gets STUCK on it all the time. And hey, when it's the bigbad, great, sit there and take out his legs while he clips into a wall... but when it's HALF YOUR SQUAD... you're screwed.
There's no melee, AT ALL, even on mechs equipped with Melee attachments!
The writing is like that of a Teen Titan's show (no not that one, the one meant for 5-7 year olds). Your fellow pilots show no emotion have no quippy or memorable lines, and even when you commit atrocities to make the $$$ they fail to have an opinion one way or the other. They also have NO story of their own, so... hope you made something up in your head.
Overall: Not really what I expected out of MW5 and 17 years of waiting. In the past, MW games have had great (if cheesy) stories that compel you to act! But this one is inane, thin, and completely forgettable. It's a great mech fight simulator... but we already have MWO for that and the two are hard to tell apart.
So, I give it 2 stars because I came for a sandbox AND a story, and all I got was MechWarriorOnline 2.0.