I have been using a lot of the latex/water based filler made by Famowood It dry's fast and sands easily. The colors are generally a close match.
I will mention that it will shrink, and or crack if you use it to fill anything that is particularly deep. In that circumstance it is not the right product. A polyester filler, or a tinted epoxy becomes the better choice. The defects I fill, are generally very small, or nearly invisible to begin with, so this isn't an issue for me.
I would avoid the water based fillers from Zar, and Elmer's. I tried both. The Zar took too long to dry, and was especially difficult to sand. Every product I have tried from local paint, or hardware stores is generally sub par.
If you have to spread filler over a large area, the soft plastic spreaders sold for automotive fillers work work well. For large cracks, and paint grade work, I would use bondo, or another equivalent body filler.
Michael Schwartz - Waitsfield VT
Shopbot prs standard 48x96. Aspire. SB Link.