25i

Considering the current Coway price tags, I prefer Alen. I have the Coway Airmega 400S and 300S and then recently got the Alen 25i for my small office. Alen hands down has the most pleasant sound. Plus they come with a lifetime warranty if you buy their filters which are reasonably priced.

Here In US we don't have Phillips so much, so I've never had one, although they do some popular/common in posting in here and are probably OK. I have multiple Levoits though and love them. As for being quiet in sleep mode you might want to look at th Levoit unit sprout, that is more for a nightstand

I have the Alen 25i in my office and would also be great for a small nursery. Only 40 db at its highest setting which is great for babies since you want to keep it under 50 db. I also really like how it sounds. A 35i or flex would also be a great choice. I like the flex because it’s a 45i without al