There is no Xenogears 2. There is only the Xenosaga series that was meant to be the prequel but due to licensing is not "officially" a part of the series.
Back on topic! I loved Xenogears. Regardless of the shortcomings of disc 2, I enjoyed every minute of it. I loved the battle system (the combos!) and also the characters. Though some say that the characters are not fleshed out, I believe that the main ones are. They all have some sort of history and reason to be a part of what they are fighting for. They are not your typical "Oh hey I can fight, I will go with" characters, they actually have emotions and positions on certain subjects. You will not regret buying Xenogears, so get it!