I like that it's easy to use through any device with internet access (including my phone).
It does not have an offline option for when there is no Internet connection available so make sure this feature exists if possible! Otherwise, great program overall but try other options as well before committing yourself fully into one solution over another - all solutions can be useful depending upon what features are needed in each of them. We've been able to find our email correspondence easily from anywhere we happen across wifi or data service while traveling / out at conferences etc.