Ajax - United, great final. I think we all would have wanted it to take place in the Champions League but that's not too realistic for Ajax anyway.
For Ajax this would be a trophy far more valuable than the league title (which Feyenoord won this year), Amsterdam and the rest of the country are all longing for this to happen. It's very different for United and their fans, the Premier League is more important and winning the Europa League is only valuable for what it means in terms of playing Champions League next season.
I think two styles will clash and I know many united fans hate the fact that they are the defending side in this comparison.
Ajax have had a great 5 years with Frank de Boer in charge but the last two seasons the football wasn't as attractive and offensive as we like to see, they tried, but it somehow didn't work anymore. Peter Bosz took over, which was a controversial choice because he has a history with Feyenoord. The first two months were very bad, got knocked out of the Champions League qualifiers, lost a couple of games in the Eredivisie and he fell out with a few (former) key players. But slowly the team went on to play better and better, a few young guys got a chance in some Dutch cup games and in the Europa league group stage and presented themselves as potential first team players (especially CB Mathijs de Ligt and RW Justin Kluivert). When all of this came together in the second half of the season, Ajax started playing some really good football, the best I've seen them play in the last 10 years. The home games vs Copenhagen, Feyenoord, Schalke and Lyon were all very impressive, if they can reach that level in the final they will beat United easily. Ajax plays very offensive football and have been exposed defensively for that on a number of occasions (lyon and schalke away) but on a good day they will overrun the opponent. Ajax creates a lot of chances but our wingers lack efficiency in goalscoring. The first leg vs Lyon was 4-1 but could have been 9-4 as well.
United on the other hand is the big rich club who have Mourinho as their manager and play a negative sort of football. I hope for the sake of football around the world that Ajax will win this. I'd say united is the favourite to win it though, a few very good individuals and a manager who knows how to win a final. If Ajax wins, it will be done in the spirit of Johan Cruyff with mainly home-grown talent and very attractive to watch. Most finals turn out to be a bit dissapointing but I will be in the stadium in Stockholm to cheer on the Ajax lads, win or lose, they've entertained us a lot this year and deserve our support.