I have straight short Asian lashes, that point downwards (and thus loses curl almost instantly). This is probably the best mascara I've tried, because it is the only one I have kept! The comb is excellent as I prefer this style rather than bristles, no matter what size or how well designed. I initially used this without a primer, and the effect was average, lost the curl somewhat several hours later, smudged slightly under the eyes. This does clump slightly for me if I'm heavy handed
Now I tried it with Shisiedo the makeup original mascara base, curl, base and Iconic -- the curl stays for 12+ hours (until I wash off) and there is no smudging or melting. Again it can clump as I am heavy handed and less nimble using my right hand to apply to my left eye.
I also use Too Faces shadow insurance primer on the lids but for the times I didn't I never had smudging issues, it is a safeguard for more testing climates and environments.
As for its effects, this adds moderate length and above average separation. It is not a drama mascara, although I do not want that effect ever... Now that one's technique is perfected, I do not know if I want to try and test other brands.