Stay with the established international brands. Get champ.
Micromax touch screens are not at all good.
So, if your sister has small fingers, get her champ. its a pretty decent device.
If your sis has large or thicker fingers, stay away from touch screens in this range. Upp it to 5 or 6 and get any star, corby or wave. (I would pick wave for having a smartphone OS and full access to Samsung app store)