If you wanna experience snowfall, good cafes and some offbeat treks, it is the best time to visit. I was there at the New Years and it was packed but now it would be the best time to visit.
Recently i had came from kasol. On day one it was raining and the weather was very cold. so if going take your rain gears too. if you want to experience snow go to Tosh which is around 30 km from there . you can hire a taxi from kasol to Barseni and then can do a small hike to tosh.