In England I'd put Klopp's achievements uch higher. To get Liverpool their first league in almost 30 years is a big deal. Then obviously he's done much better in Europe. All with a much smaller budget.
Also don't forget Mourinho's first stint. At least as impressive. Again Chelsea's first league, not just a continuation of winning ways. He also changed the game to some extent. You couldn't start a season slowly anymore and that was something United had to sort out from there on in.
So comparisons to Fergie are miles off.
The debate is has he been better than Mourinho, Klopp or Wenger in England.
Well in England Pep has won 3 league titles in 4 years, and is on the way to win CL too and “treble”. You may argue Klopp has spent less money and it’s harder to win things with Liverpool, which makes his feats more “admirable”. But no matter how admirable it’s is, Pep still won far more trophies in England than Klopp (8 or 9 trophies in 5 years vs 4 trophies in 6 years)
Mourinho has his up and down, overall he won 9 trophies in 8 years, but he has spent a lot of money too with Chelsea and us, his brand of football is boring, his man management is self-destructive, and he had failed at least 3 times for Chelsea, us and Spur. So I don’t think he can compare with Pep.
Trophy/achievement:
1. Pep - 8 or 9 trophies in 5 years (1.6-1.8 trophies per year)
2. Mourinho - 9 trophies in 8 years (1.1 trophies per year)
3. Klopp - 4 trophies in 6 years (0.7 trophies per year)
3 Wenger - 10 trophies in 22 years (0.5 trophies per year)
Legacy:
1. Wenger - “Invincible”. Master of Economics - Always maintain top 4 finish despite working with little budget
2. Klopp - won league for Liverpool first time in 30 years. Won CL.
3. Pep - won the league with record breaking 100 pts. (On the way to win “treble”)
4. Mourinho - park the bus. 1-0 is the most ideal result.
Brand of Football:
1. Pep
2. Wenger
3. Klopp
4. Mourinho