Yandex offers unlimited users (up to 1000, then you have to contact them and I guess they will allow more) and claims unlimited storage, zoho free tier is 25 users and 5 GB storage/user.
I tried Zoho last year after hearing multiple recommendations and it was nothing but problems with spam coming in and my outbound emails being incorrectly marked as spam. I even had SPF + DKIM tested and working from the start! Not sure I would try them again after that experience.
Doesn't seem to support addresses from other domains though.