I played 4 strings for years, mainly because I couldn't find a 5 I felt comfortable with.
Then I found a Marleaux Consat Custom 5 and it became my main bass. Couple of years after that I found an unusually light Stingray 5 too.
I sold most of my 4s at that point but I still have an Urge2 and a fretless 4 Status, but I never take them out. I usually get piano scores and I never know when that B string is needed, so it has to come with me.
I'm now at the point where a 4 feels like there is something missing.
I'm really picky about bass weights as my back is knackered, and I've had multiple hernias, but I hope to find another light 5 that suits. Lots of 5 strings seem to have about 48mm nut widths which is too wide for me.
I will be keeping the Urge2 as it is the finest slap machine I've ever played, but the fretless might go.