Well I actually started out playing 4s and I've ALWAYS had a lot against them! OK, the truth is I started studying piano. And then bought an upright bass. What the hell? I'm trying to play in horn keys and this thing called a "bass" doesn't even have a low Eb to play? What nonsense! ...
And then I got my first 5er. Isn't this just what God intended a bass to be? ... Even the symnphony dudes noticed the same problems as I observed with their uprights with those "extender" things on them.
... As for me, I suffered quietly all those years with 4 strings and when 5ers arrived I couldn't get rid of the fours fast enough ...
This is one argument for a fiver that holds no water. Except for those few who tune down to subsonic pitches every bass has a low end limitation. How do you play a low Bb or A on your fiver? What a useless piece of crap it is! How can you possibly dare to call that thing a "bass"? If the lack of a low Eb is a deal breaker for you did it never occur to you to tune to D standard?
I understand perfectly well the desire for a low Eb. I have been tuning all my basses in fifths starting on C for over a year. The extra low notes I gain that way do come in handy at times but the low Eb is by far the most used of the lot. I use the others for variety more than out of need and I don't miss the low B at all. One of my fours has a Hipshot Extender key on the C string set to drop to a low A and I have never used it. By tuning in fifths I don't miss my G string either, the high A string is even better. The D standard tuning is a great option for fourths tuned four strings when you want to get a low Eb because you have the two extra low notes you will use the most and you don't give up much of your G string at all.
I tried a fiver, gave up and tuned in fifths instead. Then I tried another fiver but also tuned in fifths to get the range of a six, almost seven, string bass. Evidently the biggest problem I had with a five string was the string spacing and the fact that my left hand likes narrow while my right hand likes wide. My first fiver was an Ibanez SR505 and my right hand just rejected it. My current fiver is a Fender Standard Jazz V. It comes with 17mm spacing but I can bump that up to 18mm by jamming pennies, no I am not kidding, between the saddles. So I have gone between those two spacings a bit and I have helped my left hand deal with its wide, chuncky neck by wearing it higher than I used to wear my basses and I think that I am now at long last comfortable with an 18mm spaced fiver. I think my left hand would be even happier with an asymmetric neck like the American Deluxe Active Jazz V and the MTD Kingston's have but those will have to wait until I can afford one.
It is possible then for a five-o-phobe to be comfortable with the breed with enough effort. I think my fours will always be my goto basses but I like the fiver because it gives me a higher voice for chording (and melodic work should I ever learn to do that) while letting me instantly switch to a low voice for traditional bass lines and that comes in handy at times. I went back to the fiver after trying GDAE on one of my fours for a while. I loved the high voice for some work but missed the C string, a lot.
BTW, a lot of the "symphony dudes" are starting to do what I do: tune in fifths, CGDA. Technically I do what they do, I learned the trick from them. No more C extensions, no more five string basses, life is good. In fact there is a substantial amount of evidence to support the contention that the double bass, the prototype for the bass guitar, was intended to be tuned CGDA from the beginning.
Ken