The former Cardiff City boss admits he is strugglng to pick a clear favourite, but believes at least five teams will be in the mix come next May.
"Manchester City and Chelsea are obviously the two big spenders and they are the teams with real depth and quality in their squad," he said.
"Arsenal manager Arsene Wenger has bought really well in Alexis Sanchez while Liverpool, who came so close last season, have added four or five quality players, although they have lost Luis Suarez.
"So it's going to be interesting. There are no clear favourites for me but there are four or five clubs in the race and it's going to be exciting."
And of those challenging the 'big five', Mackay is convinced Everton and Tottenham could be genuine contenders for a Champions League spot.
"Everyone looked at Everton last season and were impressed by them so I think they have a chance again. Roberto Martinez has strengthened his squad and Lukaku has now come in," he said.
"It will be interesting to see how Mauricio Pochettino will do at Tottenham. He now goes in there and it will be his chance to shape that team in the way that he wants.
"They are always a club who can make the Champions League spot but you can't look past the two Manchester clubs, Chelsea and Liverpool."
And whoever walks off the with title next May, Mackay believes they will have their hands on the prize for the most exciting league in Europe.
"If you look at Spain you have Barcelona and Real Madrid who have world-class stars, and over the last few years Bayern Munich has been up there with them," added the Scot.
"But that apart, in terms of the league and the excitement of the league and the fact that the variety of clubs in the last few seasons could win the league, then I think the English Premier League is right up there with them."
Watch the kick-off to the new season when Arsenal entertain Crystal Palace live on Sky Sports 1 from 5pm this Saturday.