Got my first 5 string a few weeks back and immediately warmed up to it. So much that I don't even want to play my 4 strings anymore. The 5 just feel right to me although I use the B for a thumb/palm rest primarily unless it's needed. Trying to justify keeping a 4 string on hand, can't come up with a good reason. Anyone buy a 5 and just play them exclusively now?
Why be so hasty? It's normal to be 100% into the new five-string, but why does it have to be at the expense of the four-string? Lots of players come back to the four-string later, either integrating it into their five-string playing, or sticking with it exclusively for a period of time.
How can you be certain that in the months and years to come, you'll not have any reason at all to play the four-string? Trust me, your perceptions and feelings will change over time. When that time comes, you'll be glad you didn't overreact to the "new toy" euphoria.
MM