A lot depends on how much you wish to spend. I bought a Coby Kyros 6" tablet through the internetlast year for about £60 and it is giving sterling service as a PIM. The diary and contacts sync with with MS Outlook 2013 using Companion Link and the built in E Mail is first class. I do not use this machine for much else though it has full internet capability. It can also connect to the internet through my 3g dongle.
OnePlus 5T review: Hands-on