I switched to 5 string 10 - 15 years ago. Loved it. Enjoyed the challenge of learning something new, but still familiar.
Stayed with the 5 for a few years in various bands but one day I just switched back. The 4 felt more comfortable, more natural. Also I suspected that learning the 5 was kind of a distraction from studying the 4. I was a very long way from a deep understanding of my instrument and I made up my mind to learn more of the 4 before considering other disciplines.
Happy with my choice, hope you'll be happy with yours.