Allow me to go a little more in-depth with this, I am tired of seeing the chung master race everywhere. Sure, he's the most noob-friendly class, but he is THE most boring to play.
Before I go any further, I have two Eves, nemesis and Empress, both level 51. So my argument may be incredibly flawed.
As far as PVE goes, they are fairly similar. While nemesis has a ton of party helping ability and isn't half bad at doing solos, she doesn't have the burst damage that Empress has.
It may sound silly, but Empress's actives are incredibly good. One fully charged Mega Electron Ball (with her other passives filled) can easily overpower a ton of monsters, and thanks to the explosion part, it can do some good towards mobbed enemies.
While Empress doesn't have many great special actives, she does have heaven's fist, a very useful skill in Hamel, as well as a few sections in Velder, as a ton of enemies are in long, vertical sections.
Now, here is a little segue on skills.
First up, empress/Architecture... As Nihil said, Eve's actives are her main attraction, so you should get each and every single one of her active skills. Oberon Guard can do massive damage on mostly super-armored monsters, as well as giving decent mob control.
Mega Electron Ball, even without all her amazing passives, can still hold its own as the strongest active in the game. An easy 700% magical damage through one charged ball of electricity. And with the special skill note, it becomes VERY spammable.
With her passives, her MEB (as well as regular electron balls) range increases by 40%, damage increases by 10% (totaling around 770% damage), and cost decreases by 30%.
Spitifire is great with mob control. It hits every enemy within the fairly large range around Eve for 450% magical damage. It's an instant cast move, too!
Her special actives aren't really worth mentioning, but she has a couple of good ones.
In specific, I like heaven's Fist, Assault Spear, and Electronic Field. Heaven's fist has infinite vertical range and deals a flat 3800% damage hit, as well as shocking the enemies.
Assault spear deals 2300% damage, so it's a little more spammable. I enjoy this move because it pierces through enemies, and so long as there are no obstacles, it continues going down at a 45 degree angle.
Sonic Wave is really debatable. I think he does about 7 hits of 300% physical attack damage, but I can't be too sure. And it's incredibly lag unfriendly; it takes a while to cast. Some people like sonic wave because it gets more hits with the note, but it still feels pretty lackluster.
I don't have much experience with genocide ripper, but I hear it's good on large bosses.
Surface cutting is absolutely worthless.
Don't get it.
Now on to Nemmy/Exotic.
Her actives are not so stellar. On Metal Dust Aura, sure, it may cause more set effect/element procs, I find that the low damage output makes it a little weak.
MEB is there. It's still strong, but not quite as strong in the hands of an Empress, though.
Spear burst is OK, as it hits with 400% damage, but I never mind to use it much.
As for her passives, her most significant passives are Divine Aura and Concentration Aura. Divine Aura decreases the mana cost of buffs by 30% and increases duration by 10 seconds. Basically, this means that a magic aura will only cost 50MP to cast and lasts for 55 seconds.
If you're crazy and go the selfish route, Magic Adrenaline will increase your damage by 45% for 20 seconds, for 70 MP. This will make you a goddess of DESTRUCTION AND MAYHEM.
Enhanced nasod Weapons has a 4% chance of increasing the damage of a regular attack by 40%. Meh.
Elegant steps increases her base movement/jump speed. Handy for PVP, if you go for the fast movement thing.
Iron spirit is absolutely worthless, as Exotic doesn't have many physical moves.
Now, onto her special actives. Hornet Sting is decent. it has a fairly large explosion, but the damage is... Meh. Stick with Atomic Blaster.
Explosion Impact, now this is a great bossing skill. I don't have the exact damage calculations, as the explosive orbs are a tiny bit hard to count, but it's really worthwhile to use on large bosses or stoic (super armored) bosses.
Iron Scraps is one of Eve's most widely used skills. In total, it does about 3000% damage, it has excellent mana regen, a nice and wide hit range, and it casts instantly!
Done deal. GET THIS SKILL.
Queen's throne is also really awesome. It's like Armageddon blade, but gives you infinite airdashes (*ZOOOOOOOOOM*) and a second attack to your regular physical attacks. The mana regeneration on this move is absolutely insane. Chances are that you'll completely fill up your MP bar before the skill duration is half over.
Basically, it's a double-damage buff. If you add in a magic accelerator, ohh booooy...
I haven't really gotten Junk break because I'd have too much fun with Queen's Throne, but I hear it's good on large/stoic bosses.
Atomic blaster is a really nice 100MP skill. it has a small proximity, but the damage on it is really nice for a 100MP skill.
Atomic Shield is really nice, too. It's incredibly helpful on bosses that spam projectile attacks (nasod Inspector). It also decreases damage taken for all other people inside the large bubble!
Final thoughts on this dissertation?
Personally, both Eves are really good and it's really hard picking a favorite. Personally, I prefer my Empress, but that doesn't go without saying that nemesis is amazing too.
In the short run, Eve may not be fore you, as she requires a ton of time and practice before she becomes great.
In the long run, however, she can be one of the best characters in the game if you play her well enough.
That's just my 2 cents, though! :B