PSV - how did he have a disastrous run mate, he was their for just over 1 season - won the league in his only complete season in charge and then got head hunted by Valencia the following October - PSV went on to retain the title btw with Koemans team.
Feyenoord - as you say he was rbilliant at, arguably his greatest acheievement as a manager tbf.
Southampton - he was brilliant at, tok over a team guted both his seasons in charge and got them finishing higher and higher each season - and imprved on what Pocch did there as well.
Vitesse - done well and qualified foe Europe with an utter monnow
Ajax - won the league 2 out of his 3 full seaosns in charge, 4th season PSV had a blinding season and he payed the price for having a poor year. Overall - looking at his time in Ajax a comparrision could be made to how Mourinho and his tiem tends to go at a club, god three years then fourth season a bad one (given an abbrassive managerial style that can maybe be expected though unkless your Fergie)
AZ - he took over from a LVG at his peak, who at that time was a much better manager and more experienced - and AZ he couldnt get to reach that level that LVG had done, think from memory though the team was also basically gutted of all it's better players so was a poor choice to take them over mate.
Benfica - came third, won the cup, and reached the QF of the CL mate (losing to the winners Barca), and wasnt sacked but left to join PSV,
Valencia - the one job you can say was an unmitigated disater on his resume - but it was 9 years ago now, and he made the huge mistake of going head to head against a core of veteran players at the team and paid the price when they stopped playing for him, same situation happened with Chelsea last year with Mourinho and you saw the results of it mate.
As an interest the three players he wanted out the club which led to all the problems, one of them threathened to retire if he wasnt played every game, Canazres - he subsequently did at the end of the season when Valencia released him, another Abelda (the captain) sued the club to try to get out of his contract and publicly opened up on Koeman at a press conference (guven he was a huge fan favourite you can imagine how this turned the atmosphere poisonous with the fans for him) and Angulo who at that time in his career was basically finished as a player - went on to play one more season (badly) and only played about 15 games more before retiring.
As i said the situation seems very similar to the situation at Spurs when Pocch faced a split dressing room over the Adebeyor and Kane argument, only dfference being the majority of the Valencia team sided with the senior players (basically he badly misjudged the influence those 3 had) and Abelda was a cult here with them, meanwhilst at Spurs the fans got behind Pocc due to Kane and the younger spurs players backing
As an interesting point though heres a list of managers he has taken over from.
LVG - AZ
Hiddink- PSV
Trappatoni - Benfica
Pocc - Saints
some big boots to fill in each account there
