There are plenty of putties out in the market place. I have had good luck with two:
3M acryl blue - this dries fast, and is my choice for filling small nicks where strength is not an issue. It feathers very well.
Evercoat Eurosoft - this is a catalyzed putty, which is mixed with a hardener to become actives. This stuff is wonderful - becomes hard enough to work with a razor blade in a couple of minutes, and sand in about 15 or so, depending on the temperature and how much hardener you add. It is good for corners or anywhere you need your putty to have strength. You will find a short article on my website on how to use it by following this link:
http://wmunderway.8m.com/cont/putty/putty.htm
Kurt Greiner
Warship Models Underway
www.warshipmodelsunderway.com