Would really like to know because I've had some trouble beating Dragon Quest VIII, I played about 60 hours of it and I wasn't ready to see the ending anytime soon. It's not that it was bad, I felt it was excessively long and its longevity had a lot to do with leveling up. Which happens with every RPG, but this one was particularly heavy on that aspect. I don't know. 
Anyway is Dragon Quest IX better than VIII? Or if I didn't enjoy it I should just give up on this series as a whole? Should I try any particular Dragon Quest game?
And last question, do the stories share some common aspects or is it like Final Fantasy where stories are completely different from each game with some recurring elements but that's it? 
Thanksss

DQ IX lost me with it's custom made characters, giving your party members little to no personality. I stopped playing after a few hours though so maybe your main character makes up for it (who is also custom made by the player).
 
DQ V is easily one of my favorite games. Before giving up on the series you should at least try that one out IMO.

Hey! I have to know!

Dragon Quest IX took almost 80 hours for me to beat. This was my first DQ game and probably my favorite game of 2010. It has really raised my interest in the series and I will be checking out other entries in the series.
 
I think that asking if one game is "better" than another in a series is pretty subjective- What would make it a "better" game to you, personally?
 
 I can say for sure that a chief complaint among fans was the fact that the characters weren't story-based. That meaning that they're just randomly generated or user-created to fill party roles. But that's sort of defeating the purpose of DQ IX. The point of DQ IX is to play with your friends and have them fill those roles and experience each others' worlds and stories together.