I own 3 ukes: a 4 string, a 6 string, and an 8 string.
I play the 6 string the most. I just like the overall vibe the best. The sound is fuller and has a chime-like quality that I just love. A regular 4-string sounds small and thin by comparison.
Finger-picking is definitely going to be trickier with any doubled strings, however...
I find that plain old strumming is actually EASIER when you have more than 4 strings. The strings feel closer together (actually, the spaces between courses feel narrower), so the strumming finger(s) glide across them with less resistance or 'bumpiness'.
As for fretting chords, it stands to reason that it would take more pressure than with 4 strings, but I have big hands, so I don't perceive it as being substantially more difficult. I just have to be mindful whenever a barre is involved.
Fretting the common shapes is absolutely no different than with a 4 string. Restringing is no hassle at all. The sound is worth it.
So I'm definitely in the narrow niche of uke folks who prefers having more than 4 strings.
Sometimes I think I want an Ohana Tiple (10 string), but at that point, restringing becomes a 'resource management project'.
All that said, I like having different instrument configurations for different applications. There is no one-size-fits-all uke for me.