I do not have experience with your other tent, but do own the Hilleberg Soulo.
The Soulo is a fine one person tent with usable vestibule space. It is light for such a very strong tent. The tent can handle very heavy snow loads easily. Keep in mind that this is not a tent I'd want to spend days in in a storm because it is small inside, but that's just something all these tents will face.
The interior is bright yellow and cheery. The construction is top notch all around. The double wall construction means it's easily 10-15 degrees warmer inside the tent than outside when all sealed up. I personally prefer double wall tents because they have less condensation issues and you get an extra layer of security if something should go wrong in the exterior shell.
The Hilleberg tents are not treated with a fire retardant which means the fabric is going to be several times stronger than tents that are treated with that kind of chemical. The tear strength therefore in case of damage (from an ice axe, crampon, etc.) is going to be much better than other tents for camping in harsh conditions. Their Kerlon fabric is the strongest I've seen in a tent. Personally in bad conditions I'm much more worried about a tent being ripped to shreds in the wind than catching on fire so I'm comfortable with this engineering trade-off.
The guylines add significant support against winds. I suppose you don't technically need all of them, but my overall view is if the designer of the tent put guylines there, then it's best to use them. They are not a problem for me and I feel more secure with them in place even if camping below treeline out of the wind because you never know when wind could come up. The guylines on the Hilleberg are designed to wrap around the exo-skeleton poles and then go to the ground. This adds considerable strength vs. just attaching the guy points to the bare fabric. Once guyed out, this tent is extremely strong.
The Hilleberg vestibule is setup so when open no rain/snow can enter the sleeping area. The EV2 appears to have the typical vestibule where it allows rain/snow to enter when the door is open. But I need to see it to confirm. I really hate vestibule designs that allow water/snow to enter the floor area of a tent. It's almost as if these tent designers have never camped in wet conditions because if they did, then they'd realize how bad an idea it is.
The Soulo vestibule is good for storing most gear, but I wouldn't normally bring things like snowshoes in, etc. as it would be a tight fit. I suppose cooking with a canister stove is possible, but I'd be extremely careful with other types of stoves. The vestibule is parallel to the sleeping area on the Soulo so you can easily lie in your sleeping bag and access your gear or keep the vestibule open for ventilation, views.
There is decent room to sit up in the Soulo, I don't know about the EV2.
I have a full review of this tent posted here:
You may also consider the Hilleberg Jannu which is larger. Or if you want the lesser weight, the Hilleberg Unna could also work but you don't have a vestibule at all on that tent.
Hilleberg makes great tents that are tested and used in the hardest conditions on the planet. I trust them above all others. Hope that helps.