One of modern time greats no doubt, but in as far as Chelsea is considered, hard to judge conclusively really. Like I said imo his previous work is not a factor in Roman's decision, instead it's his familiarity with the club and the respect and love he has here. Had we been going by past records, Roman would have signed up Guardiola, a man who has a track record of winning the league every season and the CL 2 times in 3 years, the one trophy that is his most sought-after.