PGR4 brings back that flawless blend of arcade and sim racing w/ great new cities, bikes, and stunning weather effects.
But once you add the pouring rain or the falling snow to a track like the 'ring, then you have what I consider gaming bliss.
PGR4 has fixed the jaggies, added more cities and better track layouts with more narrows and better turns, and used the weather to create really exciting and sometimes challenging moments that other raceing games don't come close to creating.
Also, if you don't have the Microsoft wireless forcefeedback wheel, you should. It works amazingly well with this game and really adds to the experience, especially when you play in cockpit camera w/ the surround sound turned way up. It's an insanely immersive experience that has been putting a huge smile on my face all day.
Bottom line, PGR4 is the true sequal to PGR2 and should make all the fans of the series pretty happy. The bikes are a little overpowered, but it just adds a little more challenge for us car loyalists.
More than anything though, PGR blends sim like challenge with arcade like speed and fun for what I find to be the single most fun racing experience anyone can find on any console. It's not hardcore sim enough for some of the Forza loyalists, but for those looking for eyecandy and really unique tracks, this game is a must have in every respect.