i guess you need to improve your english?

Finding the right job is all that matters.

more detailed information needed to make a comprehensive analysis.
have you married?
how old are you?
what do you do in your company?
do you like what you are doing in the company?
as far as you can expect, do you have a bright future in the company?
why do you want to leave your hometown for those tier 1 cities? are you thirsty of the taste of fierce competition?
which one is more attractive to you, a peaceful and predictable life or a stressful, adventurous, arduous but probably promising life?
do you know how expensive the rental are in tier 1 cities, and the prices of daily sustenance?
do you take seeking job in beijing as an adventure? do you like to take adventure?
have you prepared well for the life in a tier 1 city phisically, mentally, and most importantly financially?
do you have garnered sufficient working experience that is enough to touch employers in tier 1 cities and make them be willing to hire you? or do you have anything special to persuade them to hire you?
I occasionally run into Beijng bar days ago and skimed through what's going on over there. I found lots of guys like you gethered there. I guess maybe you can get some clue and cue over there from what they share in the bar.
in my opinion, if you have some specialties over others or if you are adventurous in nature , you should pursue your heart and dreams. otherwise, think tiwce before you make a dicision.