No one can really make that decision for you but the best advice I can give is seek out any watch that you're considering spending money on and hold it in your hand. Product photos, specs, and reviews rarely do justice to the personal reaction you'll have to the piece itself. I've been disappointed by watches that looked perfect on paper and been surprised by pieces that I never would have considered from just looking at them.
What did it for me when I bought my Rolex (2016 Explorer I) was the how the quality of its finishing felt in my hand. It practically vanishes when it's on my wrist thanks to how comfortable and unobtrusive it is but the materials, fit, and finishing on it show undeniably where a lot of the money went.
I am not a fan of the overly complicated watch - I mean complication in the horological sense. I hadn't heard of Waldan before your comment but they aren't my style. Under the right circumstances I could go with a Navitimer but overall Rolex's aesthetic style just appeals to me more.
There is no right or wrong answer, especially when it comes to something as subjective as this. If you like the look of Waldan take a look at the Omega Speedmaster which has a fantastic history and a similar style. IWC probably has some pieces you would like as well although I always thought they were a little expensive even compared to other luxury watches.
Browse Chrono24 or Govberg and you'll see a few brands you haven't heard of as well and maybe something else will pique your interest.
No reason per se... Among watch fans, those who do like Rolex like it for the history, the assumed quality, the in-house movements. Of course other brands have the same prestige and history, brands like Breitling, Audemars Piguet, Omega, etc... I think these brands are valued over some of the smaller brands because of history and certain recognizable designs (Audemars Royal Oak, Rolex Submariner, Omega Speedmaster, etc...).
This Waldan brand looks interesting, definitely dressy watches, I'm sure they're quality. I'd say go with what you like.
For all the Rolex fans here: why Rolex over say Breitling or Waldan (I like the look of the Waldans the best)?