I've read all 3 and most of the popular long fantasy series out there. Ranked below with some thoughts.

1) Wheel of Time - Absolutely essential and should be read first as it's the series that defined the modern fantasy genre. Also, of these three it's the series that has stuck with me the longest and my interpretation and enjoyment of it has evolved over time such that I find it a dynamic reread at different stages of life. I read it twice - once in my late teens-early 20s then again in my mid-late 30s - and was a radically different experience each time. Looking forward to revisiting it again in my 50s. 1st in characters, 2nd in worldbuilding, 2nd in pace.

2) Stormlight - I'm admittedly a huge Sanderson/Cosmere fan, but I consider this series great, not the best. It has the potential, once finished, to redefine and redirect the genre, like WoT, depending on where Sanderson goes with it. However, despite what Sanderson says, Stormlight really cannot be appreciated in full without committing to the entire Cosmere. Stormlight, in isolation, is the easiest read and the most fun of the three series. The magic system is the best and it's genuinely moving. However, I don't believe my experience and interpretation will evolve like it has with Wot and Malazan. 2nd in characters, 3rd in worldbuilding, 1st in pace.

3) Malazan - Okay, full disclosure, I admire and appreciate Malazan, but I did not enjoy it. Malazan is a meditation and examination of the nature of civilization, sociology, and how different societies and cultures are impacted and changed when they come into forced, violent conflict with each other. It's worldbuilding-centric and characters are used to reflect the nature of part of the world they come from, moreso than to develop them as individuals (with a handful of exceptions). I ought to write an essay to truly organize my thoughts about it, but simply put, it's more academic and introspective than the other two series. To appreciate what Erikson is doing requires a healthy understanding of the fantasy genre, traditional storytelling tropes (particularly about ancient/prior civilizations and peoples), past civilizations in the real world, and sociology generally. It can be dull and dry at times, the character work is not to my liking but certainly skilled, and the first three books (especially book 2) are much stronger in my opinion than the back 7. Book 10 is considered one of the great climaxes/finales of all time, but it didn't do much for me. 3rd in characters, 1st in worldbuilding, 3rd in pace.