It's such a difficult call to make. Personally, I could see any one of United, City, Chelsea or Liverpool winning it and then Arsenal and Tottenham are of a similar standard to those four sides anyway. Liverpool are less fancible, as I don't think they possess the same quality in their squad and have a dodgy defence, but do have a great attack and a class manager.
Running the rule of the title credentials of those sides I would say United and City are the most well-placed sides to win it, Chelsea third favourites then I'd side with Liverpool over Arsenal or Spurs personally.
In regards to United I think we have a very strong squad, bested by only City, a PL-proven manager who wins everywhere he goes and a formidable spine that now boasts big personalities like Zlatan and Pogba which we've lacked for years now. An period of acclimitasion is expected under a new and completely different manager, but we look good in all departments IMO. There's the Rooney issue which could be the undoing of us in either winning the title or not though.
City - as alluded to above - have the best squad in the league, possessing a wealth of attacking talent, as well as potential with Stones, Sane, Sterling, etc. I think they needed an injection of youth to what is an ageing and injury-prone squad in some departments, but their squad still looks a bit unbalanced to me. As for Pep, I believe his football here can excel but he's trying to be far too clever (Clichy & Sagna experiment) when he could field a normal side and easily beat the minnows of the league like Sunderland. Against better opposition - of which there are many - he will come unstuck no doubt. I actually think City will be slow-burners this seasons so it's a question of how quickly the players can adapt to Pep's tactics aswell as keeping Aguero fit which is of paramount importance.
Predicting Chelsea to finish third. They're are still an enigma, as I don't know just how much they underperformed last season. Hazard definitely looks back to his best, so with him they have a chance this season. They've neglected an ageing defence for too long though and that needs to be addressed in the way of a CB and LB. Conte will know doubt make them solid and compact defensively though and Kante's incredible. Free reign at the league bodes very well for them too.
Hate to admit it, but Liverpool do scare me a bit. Look how much no European completion aided them last season and it's proven to be a huge plus. Just how much I'm not sure, cos they are Suarezless now. Klopp having a full pre-season to work with his team is huge though and practically ensures they should have one of the bestbstarts out of the top dogs. Mane's a huge addition and they have more swagger going forward than anyone right now. Fortunately, they are so suspect defensively though - IMO their defence is really very sub-par at best and the weakest out of the top sides for sure. I think as a team their in-game management is questionable too. They play at such a high, frenetic pace that it's almost naive and could be costly if they just keep going gung-ho rather than see out the win. Expect them to start very well and tail off later on.
Arsenal and Spurs are the two sides I'd categorically rule out of the title. Doesn't matter who Arsenal sign, with Wenger in charge they just won't win it such is their mental fragility that stems from him in fact. The likelihood is they will get fourth at least, but I just think they're playing a dangerous game and will eventually fall out of they keep up their frugality in the market. Spurs won't it, cos Arsenal won't win it and they always finish below them... Seriously though, I can't see them managing European commitments along with the league to a great affect even though their signings have been sensible.