No, I'm going with the DW.
I can't stand Superhero Archer. It was like his subordinates were made to look stupid in order to make him look good. It just seemed more brawn over brain with all the FX over quality storytelling. And not to mention those neuropressure sessions.
The DW was something that was built up to, and the Dominion were repeatedly made to look a real threat, something IMO the Xindi weren't. And then you've got villians like Weyoun and Dukat who are not even in the same league as err... Dolim and whoever that chief Insectoid was.
Agreed. My vote also goes to the Dominion War. (I would have liked to see an actual poll in this thread :P)
I personally like the Xindi arc better in both ways. It had a much more complex plot, which is a good thing.
Obviously you're mistaking complex for convoluted.
This is also how I remember the Xindi arc -
Lets see if I remember this Xindi thing right.
They want to destroy Earth for poorly defined reasons. They were told that humans would destroy their homeworld in the future and they apparently believed it without question.
They test their Similar But Legally Distinct From the Death Star on Earth itself, which makes no sense storywise but the "plot" hinges on it, so they do it anyway.
The Enterprise crew dicks around in the old west for a while, then some guy from the future gives them a Xindi quarter, which is apparently enough to convince the majority of Xindi that humans won't destroy their homeworld after all.
As for this...
In DS9, they didn't have to find out why the Dominion was attacking them, they knew it from the start. In Enterprise, they didn't initially know why Earth was attacked and who were the Xindi. The Dominion war was just a war and there was nothing mysterious about it.
Wha...? I think you're forgetting that the Dominion was first mentioned back in like, Season 2! They had
no idea who the Dominion even
were back then!
And then, even when they DID discover who these mysterious 'Founders' were in Season 3, they didn't immediately jump into war.
Before the 'real' Dominion War started, the Founders infiltrated the Alpha Quadrant, set the Klingons to attacking the Cardassians, tricked the Obsidian Order and Tal Shiar into a 'pre-emptive strike' which was an ambush, tried to start a war between the Tzenkethi and the Federation... And thats all before any actual war broke out!
Heck, they replaced Bashir and Martok with Founders and we had NO IDEA.
So I don't know why that doesn't fit your definition of 'mysterious' but I sure think it is.
Not to mention, once the war does start, then we get 2 seasons, and many episodes (both before and during) where we're exploring who the Founders, Vorta and Jem'Hader were. We learn their motivations, their beliefs (or programming), and find out WHY they're doing what they're doing.
I don't remember Enterprise exploring any of the 5 Xindi races in that much depth.
Though I will admit, of course they could have explored the Gamma Q, and other Dominion races further - but what we DID get was still a heck of a lot more than the Xindi arc.