Joshua:
Nothing wrong with the EOS1 per se, but it's awfully heavy given its small/tight configuration. It weighs essentially the same as my beloved (and much bigger and comfier) BA Seedhouse 2 SL. Given Marmot's penchant for lying in its specs — I would not be surprised at all if the EOS1 turns out to be smaller AND heavier!
Regardless of model… one very pleasant surprise about "all mesh" inner is just how much wind it blocks! That was my worry (I hate even the thought of a constant draft blowing across my face all night) — so I did an experiment when I got my Seedhouse. I positioned a box fan right toward the mesh inner and set the fan on "High". Sitting inside the inner, I was surprised at how very little air movement was inside!
In the field — between the fly almost coming down to the ground and the wind-blocking mesh — I have had many howling nights outside, but feeling only very soft and pleasant air movement inside.
The second surprise: while the fly/mesh are extremely effective at blocking blowing winds, the mesh does let in slow-moving night air! For most all 3-season, it really is marvelously comfy. I would still, however, prefer an inner with solid fabric for truly freezing nights. Just about the only other scenario where mesh tents perform poorly is when camping on fine sand (desert, beaches). But even a tent with solid fabric halfway up won't do much good on locations that are both sandy and windy.
So long as the fly is deployed properly, there's really no need to worry about rain splashing through the mesh. And as stated, blowing winds are not a problem either — unless you're on a beach or a desert dune. Hope this helps.