Bilic had actually agreed to join Everton in March of 1997 but told them he wanted to finish that season with West Ham, who were in relegation trouble.
The Hammers escaped the drop by two points, so by the time he signed for Everton that summer he was already used to fighting relegation battles.
Things are different for both clubs now though, with the Hammers a point away from a Champions League place and Everton closing fast on a European place themselves.
Bilic said: “On paper, they are showing – not week in week out but very often – they are amazing and one of the best teams in the league.
“So much quality in everything. Pace, quality, individual skill, size of the squad, physical presence, they have everything so again we will have to be at our best.”
West Ham have not won a league game against Everton since 2007. But the Merseysiders have struggled to win at Goodison this season.
Bilic said: “It is a surprise. You look at their teamsheet and the players they’ve got, even in the last transfer window with Oumar Niasse coming in, from Turkey and Russia, they are a great team.
“In every home game I have watched they were better on the pitch than their opponent. Whether they are a bit unlucky or sloppy at the back, they are dominating at home whoever they play against.”