Rock Band 3 exceeds my expectations, and may very well be the greatest music game out right now.
Let's start with one of the most obvious things to mention. Rock Band 3 has implemented Gameplay for not only Guitar, Bass, Drums, and Vocals, but keyboard too. The keyboard is a great addition to the mix. It plays very similar to Guitar/Bass, but with it's own feel. I am disappointed that you can not play with Guitar, Bass, Keyboard, and Drums at the same time however. The only way you may pull this off is by bringing three singers along to play with you. This addition isn't new to the Rock Band spin off games (Beatles and Green Day) but it is new to the mainstream lineup. It works just fine, so there really isn't much to talk about if you've played Beatles or Green Day Rock Band. Before I move on, I would like to say that all previous songs (Except the Pearl Jam songs and Green Day) don't have harmonies. Likewise, keyboard is also missing these tracks (Except it is also not playable in the Pearl Jam and Green Day songs). This comes as a disappointment, but an understandable one. Certain older songs are no being re-released with keys and harmonies added though so stay on the lookout of that.
The biggest feature in this installment is Pro Mode. I have not played Pro Mode for Bass or Guitar. I'm sorry if you wanted an opinion of this, but from the videos I've seen and previous reviews, it seems to work fine. What I'd like to talk about is the Pro mode for drums and keys. Drums on Pro Mode adds another level of challenge to the game (All previous DLC works with this by the way). The game adds the hi-hat, the ride cymbal, and the crash cymbal as their own note. You can no longer hit the yellow tom for the hi-hat, and the green tom for your cymbal. It works really well, and if you love playing drums in Rock Band, I highly recommend this.
Keys on Pro Mode is something really unique. Instead of using solely five white keys, you know use the whole thing. The keyboard ranges about two octaves and is a good start for anyone wanting to learn how to play. Granted, it's only the right hand parts of the songs you play. This may be a big problem for some but it's still fun to play.
The song selection is hit and miss. I personally love it, but many people I know hate this track list. The songs are almost all fun to play but many are not overly difficult. I suggest checking out the setlist online. Also gameplay footage will be a big help too, since you can decide for yourself if it looks fun or not.
The in game presentation has been given an upgrade as well. The graphics are much prettier and everything in terms of menus flow very smoothly. The trivia before songs have been replaced with cut scenes of the band preparing and songs now rewind after the game is paused. This is a very nice feature, but I would have preferred it if, when you pause while holding a sustained note, you can still hold the note upon return. Many songs don't have long breaks and these may be the only time you can pause.
The character models are again, hit and miss. They all have a very shiny look to them and this is where people start disliking them. I'm OK with the look. I don't love or hate them. The character models don't matter much in the long run though, since most of the time you'll be concentrating on the notes.
The, "Story Mode," of this game plays well (This mode also replaces last game's story). Instead of picking a city and playing all the setlists, you pick a tour and decide on what setlists to play along the way. In each song you're presented challenges to complete. Upon completion you obtain spades (Similar to stars) to show how well you have done. The DLC sucks for these missions. Many songs from the previous releases don't work well with the missions (For example, hitting every note and receiving 3 spades but hitting 91% of the notes in a new song and getting 5). This is a fairly big mistake and I think it's a problem of too little testing. However, the missions.... still don't feel right even with new songs. They all feel tacked on and at times they get boring. Some are fun but others are boring (Use overdrive many times, or get a streak while in overdrive, or use overdrive when it's completely full). The biggest asset of story mode however is the fact that me and my friends can start a tour and finish it depending on how many songs we want, along with some moderately entertaining missions. This is cool for that game night with friends on the weekend.
The new goals mechanic replaces the challenge mode and money (Yes, money). You complete goals (Connect to the rockband.com, beat story mode, beat all songs, etc) and receive new items (Clothes and instruments). This is one of the most fun things to do in Rock Band 3...... really. Anyone who has tried to get that last achievement will know how fun it is. Anyone who hates achievements because they get nothing in return will love this, since you get new stuff for your character. This mechanic encourages players to get better to receive these cool items, but there is another problem. Players without certain instruments now can not obtain certain items because they can't complete the goals. It sucks, but anyone obsessed in making their character perfect will not like this at all. A simple way around this would have been to add the same reward for two goals instead of one, but this would have taken away some of the fun.
Now onto the bad parts about the game. The competitive modes have been removed. Instead, quick play and story mode are available online. I don't see how removing these modes helped the game, but I'm not too disappointed. It just seems odd. Also the game's peripherals are quite expensive if you plan on only using them with the game.
Overall, Rock Band 3 is the best out of the current music games. It plays great and it's really fun. It could have been more, but when so many new features are added (And they don't feel like a clone from another game) it's hard to stay mad. I'll give Rock Band 3 a 9/10.
Pros: Great party game - New instruments are a welcome addition - Pro Mode adds much replayability to the game - The goals system and story mode make for good replacements to previous modes - Great new presentation -Cool song list
Cons: Lack of competitive multiplayer - Instruments can be pricey - Missions feel lacking in some areas
{This is my first review in a long time, so I apologize if it seems oddly worded or if I made some mistakes}