Manchester United last won the Premier League in the 2012-13 season. It was Sir Alex Ferguson's last season in charge of the Red Devils. Since then, Manchester United have struggled to replicate their success from the Fergie era.They've now sacked four managers in the span of eight years. None of the managers who have taken over since Sir Alex Ferguson have had the kind of prolific success he's had at the club.Manchester United have struggled on multiple fronts since Sir Alex left the clubManchester United have not fared well in a lot of departments in recent times. Starting with recruitment and sales all the way to getting things done in an organized manner, most of it has been a mess. A lot has changed over the past two years though.Manchester United have had two experienced veterans, one promising candidate and a club legend take the reins at the club. Now it's time to take a look at who did the better job.#4 David MoyesStoke City v Manchester United - Premier LeagueThis is a no-brainer. David Moyes was simply underprepared for the role. Being Manchester United's manager comes with a lot of media scrutiny and fan pressure. Moyes disappointed fans due to his lack of clout in the transfer window and it looked like he was set for doom from the get-go.Moyes didn't last a full season. He coached Manchester United to 27 wins in 51 matches but lost 15 as well. That didn't go down well with the fanbase, who had just seen the same team win the Premier League title with an 11 point difference at the top.David Moyes was also found guilty of vetoing the signing of Thiago Alcantara back in 2014. The Spaniard, who went on to do great things with Bayern Munich, was supposed to be Sir Alex Ferguson's parting gift to the club. Moyes vetoed the signing after the telling the board that he didn't know enough about the player.Moyes' Manchester United stint was stained with confusion and he just didn't have the wherewithal to help navigate a side through an identity crisis. But the Scotsman has improved massively and is currently managing a very exciting West Ham United.Sky Sports Retro@SkySportsRetroDavid Moyes' final interview as Manchester United manager.3:08 AM · Nov 22, 2021804David Moyes' final interview as Manchester United manager. https://t.co/o1LzsjOGOt#3 Louis van GaalManchester City v Feyenoord - UEFA Champions LeagueToni Kroos has revealed in February 2020 that Louis van Gaal scuppered Manchester United's chance to rope him in after the club had almost sealed his signing. Van Gaal, known for his ego, wanted to build his own project at the club and the club did not give Kroos a definite answer. This eventually led him to join Real Madrid.Van Gaal, known for his 'total football' philosophy and successful stints with Ajax, Barcelona and Bayern Munich, splashed the cash in the transfer market. That summer, Manchester United signed Angel Di Maria, Ander Herrera, Daley Blind, Luke Shaw, Marcos Rojo and Radamel Falcao (on loan).After 10 games into his first Premier League season, Manchester United were ninth. This was their worst start to a season since 1986-87. They had suffered embarrassing defeats like the 5-3 loss to newly promoted Leicester City and the 4-0 loss to MK Dons in the League Cup.Van Gaal insisted that he'd need at least three years to build a project at Manchester United. Eventually, United's form improved and they finished fourth in the Premier League table in the 2014-15 season. The Red Devils spent heavily in the summer transfer window once again.They brought in Memphis Depay, Morgan Schneiderlin, Anthony Martial and Bastian Schweinsteiger. But the football they were playing was insipid and uninspiring. Early exits from the UEFA Champions League and the League Cup didn't sit well with the fanbase.There was a lot of speculation over Van Gaal's future and he even walked out of a press conference after being asked too many questions about it. There were even rumours of Ed Woodward rejecting his resignation during the 2015-16 season.A 3-0 loss to Tottenham Hotspur later that season reportedly turned the dressing room against LVG. The Dutchman was able to guide United to an FA Cup triumph. Unfortunately, he was sacked just two days later.While he did have a philosophy and a style of play, it didn't look like the personnel he had at his disposal were cut out for his plans. So Manchester United ended up playing a lot of boring football with the constant sideways passing turning people away. He also left plenty of deadwood at the club.Sky Sports Retro@SkySportsRetroLouis van Gaal on expectations being too high at Manchester United.6:54 AM · Nov 21, 20217015Louis van Gaal on expectations being too high at Manchester United. https://t.co/V1vTWRHNNP