Did the hard reset fix the no beep for lows problem? If so then I would definitely keep it. If it did not and you can live with a no beep for low if you just use it to give coverage over the restart 2 hour window then keep it. I did and I'm glad I have two. It's interesting how quickly you begin to feel blind when you do not have access to trend/number data.
Since the new receiver has a different serial number when you go to upload it will start a new data file. You can always look at the old file to get you average and patterns and compare them to the new file.
I use one as my primary, and the other as a backup/startup overlap. I take my main info from the one I designate as number one since it has the most data. You can still see trends and problem periods since the backup gets the most use during the 2hour blackout during a reset.
Just be aware that since your overlapping a new sensor startup or a reset that the trends are good but the absolute number may be off.