It most certainly does sand down very well. It can be wet sanded as well. I use it for everything! Except maybe some small pinholes and stuff. Squadron for the small stuff...
I bought the one lb kit a year ago. For seam filling, I use a very tiny amount of Aves. I would still have quite a lot of it, except I decided to cover my polar bear in a pretty thick skin of Aves.
I would say price wise it is pretty close to the other putties out there. You just have a higher outlay because you are getting more up front.
Q, I converted it to USD, I wanted to buy one but my pocket couldn't afford it. they sell via small pail or Pint Size...that was held last Toycon here in Philippines. maybe they already added the shipping and Tax, that's why.