This could potentially be the transfer that drags United out of their post-Ferguson malaise if they get it over the line. The money they're paying is astronomical, the world record fee was always going to be broken and it should have been us, but the fact that it will take up less of their overall turnover (19.6%) compared to their moves for Juan Sebastian Veron (21.8%) and Rio Ferdinand (19.9%) means they can earn the money back through shirt sales and TV revenue fairly quickly.
Plus, he's likely to be worth it on the pitch. Not only is he a hugely marketable footballer, he's a gamebreaker and the sort of player who will eventually be able to run games in the manner of Zidane circa 2000-2006 or Yaya at his imperious, controlling best (2011-2014). He won't be able to impose himself on the Premier League in the manner he wants to immediately, but if he stays around long enough we'll look back with hindsight and consider him to be one of the greatest to play in this league - think Drogba, unspectacular on a season-by-season statistical basis but undeniably one of the greatest strikers in English football history.
On the other hand, this is a huge gamble. Fee aside, United are signing Pogba instead of the likes of Matuidi or Krychowiak (who went to PSG) - players with more of a defensive preference who could slot in to Mourinho's rigid 4-2-3-1 formation - so this has to work. United fans will hope that Pogba will take over Rooney's role in the side long term and have just as much of an impact while he's at the club. Also, as others have mentioned, his wages are now up there with Rooney and Zlatan, which means players like Smalling, Mata, even De Gea, will be asking for a payrise sooner rather than later.
It won't be the difference between them finishing 1st, 2nd or 3rd this season, as much as Sky Sports will constantly tell us, but if he slots into the team they could absolutely threaten the little two-horse race we were planning on having with Chelsea. It'll be exciting either way, and one thing is for certain: the Premier League is about to become a force that lives up to its billing once again.