Hagu asked about Bioware games, for people who haven't played any of Bioware's previous games.
First, if you haven't played any Bioware games, go out and buy Mass Effect and Mass Effect 2. They are amazing games, showcasing Bioware at its peak.
Bioware games are Roleplaying Games. You build a main character, take her out into a world, and follow a storyline until the end. The main character gains experience and levels as you go through the game.
The main difference between Bioware games and the current crop of MMOs are Conversations. Whenever you talk to an NPC, it starts a conversation where the NPC says a line, and you choose a response from a given menu of options. The responses can cause the conversation to go in different directions and result in different outcomes.
Conversations are a huge part of Bioware games. It's quite possible that you spend more time talking to various people than actually fighting. Though there's quite a bit of fighting too.
The thing is that Bioware uses the conversation trees to deliver powerful storylines. In some respects it's closer to interactive movies than traditional games.
The next major component of Bioware games are Companions. In Bioware games, you don't just control your main character, you control a small party of characters. You can directly control your companions in combat, but usually they have some AI and you let that run, only intervening when you need to.
Your companions are very detailed NPCs. They usually have a backstory. You have to engage in conversations with them to reveal their background, and usually end up with special quests to give them closure over their own story. Usually you can also set up a romance between your character and one or more Companions.
Your companions also interact with the world, adding commentary and participating in conversations.
The third component of Bioware games is usually some form of Moral Choice. Very often the game will offer choices--especially in conversations--between good and evil, between Light and Dark, between Paragon and Renegade. The path you pick changes the reaction of your companions to you, changes the outcome of quests, and can change the ending of the game as well.
So those are main strengths of Bioware games: Conversations, Companions and Choice. Bioware combines those three elements in a beautiful way.
The main weakness of Bioware games, in my view, are the actual game mechanics. Very often they're overly complicated, somewhat unbalanced, often non-intuitive, and don't really "play" well. They're not outright bad though, and as it's a single player game it doesn't really matter if the mechanics are the best or even balanced.
As well, because companions do play a large part in combat, there's often significant effort in making sure they play properly instead of say, blowing all the mana they have on weak DPS spells when you'd prefer them to save it for healing.
In my experience, you play Bioware games for the stories, and not because combat is amazingly fun or challenging. Some people do like it, because very often you can pause and micromanage your party for extreme effect, and it's fun figuring out the very powerful stuff.
Most of the time I just set the difficulty to easy, and savor the story line.
I do have to say that I actually really liked the way Mass Effect 2 played. Though possibly that was mostly because the AI was finally somewhat competent, so I could let Garrus and Miranda take care of stuff while I sniped (boom, headshot, never gets old) to my heart's content.
So those are the strengths and weaknesses of Bioware games, as I see it. I do strongly recommend their games though, especially the Mass Effect series. That series is science fiction, and not the typical fantasy story. I am greatly looking forward to Mass Effect 3.