For me, yes.
Mind you, I'm prejudiced. I'm the guy whose players go up two levels a year, about once every ten-twelve three hour sessions, so that the campaign is 13 years old and the highest level PC is 21st. That being said, I've seen some real advantages to our style of play which would be much more difficult to do with fast advancement. Two obvious ones are:
- knowledge of character abilities. Not a big deal at low levels, but with high level play the additional time at each level means that the players have time to work out great strategies and eventually use most of their capabilities.
- maturation of plot elements. PCs and NPCs both can put long-term plots into effect. The consequences from PC actions has a chance to trickle down into the world. Interesting NPCs have a chance to grow, mature and change.
As Plane Sailing said, in fast-moving campaigns I tend to focus much more on what my character can do. In slower moving ones, I tend to focus on who he is. My preference is for the latter.