I live on Kowloon side, in part because my office is on this side, in partbecuase I wanted to experience the city in ways many expats never do. Sometimes I am thrilled with that choice...sometimes I long for the typical expat existence!
So...decide what you really want first. In my opinion, Kowloon has everything HK has without the attitude...but also without the cool urbane expat-in-Asia that makes for that attitude.
Most K-side expats pick TST and environs. For me, the area matters much less than lots of light, high ceilings, and a spacious feeling. I could not likely get the space I have in a partially furnished place HK-side for the same rent.
I chose an old building, no services, because the flat is larger (I came from 4200 sq ft and looked at flats the size of my dining room table). I have an unobstructed view toward green hills and a 5 minute max walk to the MTR. The MTR makes it easy to get anywhere. Living on Kowloon side, you'll see both sides. Living on Hong Kong Island, I find that many people just stay there. Now...if I could afford Repulse Bay...I'd change my tune ;-)
Good luck - send a note if you have specific questions.