I highly recommend Graphene. Graphene has proved capable of meeting all requirements from my client, and was sufficiently flexible to cope with subsequent changes in requirements. I am fairly new to WordPress, and Syahir (theme author) is very quick to provide advice and support assistance. I also recommend the mobile version of Graphene.
So my advice is don't hesitate, install Graphene and use it. Then install the mobile version when you are ready.