Just in case: You will still need to buy a Republic Wireless SIM card for it and install the Republic app. The SIM is available on Amazon as well as right here.
In terms of time and trouble the first thing you might want to do is check your coverage. So, before you commit to the new phone rather than after you buy it.
This is the map for the new phones on the new GSM network: Coverage Check | Republic Wireless
Here is the map for the CDMA network which your current phone uses and the 3.0 Sprint service will use – once it is rolled out: Coverage Check | Republic Wireless
During the soft launch a computer decides whether you should get CDMA or GSM service when you buy a new handset from RW. If you get your phone now from Best Buy it will be on the GSM carrier. 3.0 Sprint service is coming. Soon. -ish … (It’s a contract thing; those that know can’t say, those that say don’t know, etc.)
You may not have any service-related issues and you may not have a partner carrier preference but you should be aware that it’s a little different ‘underneath’ than the Plan and service you currently have. I am on the 3.0 Plan now and my signal strength indicator reads lower than it did with Sprint but coverage is still fine and LTE data speeds are great. Not saying you should lower your expectations just that some things work differently now that RW is out of the ROM.