... how important is Damping factor in determining what amp to buy

Here's my 2 cents.  I've had amps and avrs with damping factor specs from 50 to over 1100.  I can't say it's been a game changer for me or a crucial spec.  More and more I just want good synergy with the particular speakers I'm working with, and the best way to hear if an amp controls your speakers well is to hook it up, or audition it somehow. 

That said, if an amp manufacturer is paying attention to the damping factor performance of their products, they are probably really anal about how their products sound, and that is a good thing.  

That’s a good question. On the surface it looks like it should be very important.  The higher the DF the better the sounds would be a reasonable assumption.

Who wouldn’t want better control of the bass drivers? Wouldn’t that yield tight and accurate bass? While I’ve never purchased an amp based on dampening factor, I do have a couple Rotel amps which are listed as being 1000. Adcom is another brand that list high on the DF scale.

That being said, there are lots of very good amplifiers that have DF in the 100-200 range so maybe it’s a situation where anything over 100 is overkill?

Hegel H300 has a DF of 1,000. The new H360 is a DF of 4,000, Hegel advertises this hard in their literature and discussions, seems very important to them and I do love their top integrated units.