Just finished Omega.
It's ok; IMO not as good as Leviathan or Lair of the Shadow Broker. I think it fits very well with the vanilla game - it felt just like one of the side missions (while Lev and LotSB felt like special story events).
I found the whole thing rather predictable (though that can be said of Mass Effect as a whole) - for example,
at the first mention of a mine in Omega, it became immediately obvious that the previously mentioned Adjutants would be encountered there.
The character of Nyreen was nothing new, though I thought the backstory between her and Aria was somewhat interesting (the interaction of Nyreen's then-underdeveloped personality and Aria's strongly developed one).
But I think it would have been more interesting her character's inner conflict was brought from the past, to the present time. For example, if the now self-confident Nyreen where to find herself being influenced by Aria after interacting with her again after a long time, and is distressed by the fact.
The now-present psychological conflict could then have been a valuable point of interaction for the player - it could have been helped to be overcome out of benevolence, manipulated for gain, or perhaps even aggravated for sadistic pleasure.
I think something like that could have added a little more depth to the story than what the existing character interactions in the DLC already offer.
I thought Nyreen's death was a good thing, not for any dislike of the character, but because it was (to me, anyway) completely unexpected, and caught me completely off-guard. I had expected her to become some important character, perhaps even a squadmate. I personally liked that development, as it added a little vitality to the experience.
On an unrelated note: A general is shown playing a game of chess at the opening of a military confrontation. Oh come on, seriously
I find it a little funny that no attention whatsoever is drawn in-story about Nyreen's gender, considering that she is the first Turian female Shepard has encountered in months (or ever, as far as the player is concerned). I suppose that is to be expected, since the almost complete lack of non-Human, Asari, and Quarian females up to this point in the trilogy is somewhat of an awkward issue. But thus far, Krogan females have been explained to be rare, and I think Salarian females prefer to remain on their homeworld; I don't know what the lore explanation for Turians is.
I like the Turian female physical design. I hope they're brought to Multiplayer sometime, too.
I also like how the DLC lets us see more of Aria; she is one of the more favoured characters among fans, as far as I know.
There were a few animation glitches, as has been pointed out by Stingerhs. I don't recall ever encountering those bugs previously, so it was a bit strange (and immersion breaking).
It was funny playing Single Player Normal difficulty after playing Multiplayer. In fact, I think even Bronze may be harder than Normal.
I've heard Insanity is a walk in the park compared to Gold, though I have yet to try this.
[EDIT]Confirmed. I just replayed the (DLC) endgame on Insanity, and it didn't even begin to rival Gold. More like Silver. When you add the time perception manipulation features available in single player, it almost feels like you're cheating.
I think I'll try get that Insanity achievement next time I play through...