Short Version: In the context of Mechwarrior games, this is definitely the best of the best. Has all the best elements from the original Dos MW1 through to MW 4 and the slick gameplay from MWO. However, If you're looking for a game that brings MW into the modern age of gaming (able to compete with AAA titles, or excellent indie games out there) you'll be sorely disappointed.
Long Version: The mech piloting and combat are good but it's everything else that just feels lacking.
All the things that HBS' Battletech did to make the Succession Wars and Mercenary life in the Battletech Universe come to life seem to have been copied and slapped on to MW5: Mercenaries rather than thoughtfully adapted for a First Person Experience.
The devil is in the details. The graphics, levels, UI, and story appear to check off all the boxes on my wish list of features for a mechwarrior game but it just does not come together to create an immersive, convincing, and engaging representation of what it's like to be a Mechwarrior the way that Battletech aspired to do.
if you're hankering for some old school mech combat, this is your game. But if you're looking for something inspired that will hold your attention for any significant period of time, this won't cut it.
Rather than building on the best of what HBS' Battletech had to offer, Mechwarrior 5 seems to have haphazardly glued on some of its design elements on top of Mechwarrior Online which is a shame. Rather than build on what Battletech had done right, it feels like Piranha cobbled together a lackluster attempt to copy it. My only question is why did it take so damn long?