To me, the unique ukulele sound is lost with low G tuning (or worse, traditional baritone tuning). I have guitars to play, so no need for a uke that sounds pretty much like a little guitar.
There are definitely times when the added range is nice for picking out notes in the key you prefer, rather than being limited by the range of high G tuning, but even at that, a little innovation in bumping the melody up an octave for some passages can add something a little less ordinary than straight melody picking.
I keep one tenor tuned to low G for the above purpose, but can't bear to change over any of my other ukes. Even the couple of baritones I have are likely to end up with GCEA eventually, and one already is but with low G (which may change).
It's all just personal preference of course, but while I can see a uke-only player maybe wanting the more guitar-like sound, it's hard to imagine why a guitar player would want his ukes to sound like the guitar. Smaller and more portable I guess, and fewer strings to worry about, but I enjoy the unique sound a uke gets with high G or other re-entrant tuning.