Hi Khadeejah al-Jahani,
I personally like the Impact Hub (http://www.hubpraha.cz/en/ ) because of the location, atmosphere and what it offers. You can find a good article comparing several popular co-working spaces on Prague TV (http://prague.tv/en/s72/Directory/c214-Business/n6896-10-Coworking-Spaces-in-Prague).
I hope this helps and kind regards - Bert