I’ve saw plenty of fancy multiscale basses, but tend to avoid them at my beginner skill level. But maybe someone has experience using one and is willing to share some insights of:
Bass on,
Chris
The reality is that you can adapt to them pretty quickly, as in a couple of minutes.
I have a Dingwall that I bought about 6 months into my bass journey, it was a deal that was too good to pass by. I also have normal, non-muntiscale basses, a short scale and a fretless.
The only (very minor) thing with a multiscale is that getting your finger behind the fret when you are playing the G string at the headstock end, when coming off, say the E or A strings, can take a bit of practice, think trying to do octaves. Sometimes people talk about bass chords, up past the 15th fret, being problematic, but I don’t play bass chords, so this is irrelevant to me.
The positives of a multiscale are that they look freaking cool (IMHO), they have a very clear tone (well, mine does) and the tone is consistent across the strings.
Multi Scale basses are awesome. But like everything else there are some trade offs
Pro
Longer low strings offer firmer feel and better timbre to the notes
Advantage to those who regularly drop tuning as the string tension still firm enough and not flopping around
High string stays the same or even shorter for better bending ability and feel as well as this often leads to sweeter notes
You get the best of both world, have the cake and eat it too, 
Con
Depending on how the nut is design and cut, it can be awesome or pain to play the first fret on the low string. As the tip of the index finger is fretting the note, the middle of the finger is touching the top of the nut, this can be anything from irritating to painful if the nut is not done right. I have a few Multiscales I experience all range, my custom short scale is just a dream to play the first fret.
Like @sunDOG mentioned, 14th frets and above can offer up some fretting issue as the frets slant now run the opposite direction and your fingers are now have to work harder to get to the note, then worse hold them for chords.
I’ve got an SR806MS which has a scale length of 35.5 - 34 so not as much of a spread as a dingwall or a BTB which i think are both 37in. The main difference is that you get a longer scale length for a tighter B string without making the scale length too long for the G/C strings.
It mildly affects the upper frets and can make it more difficult to play chords but I don’t really notice it when playing,
You adjust really fast to multi frets, or I should say I did. Nothing to be intimidated by. If you pick one up and play it’s surprising how fast you forget you’ve got fanned frets. I don’t do chords so that doesn’t bother me.
As @sunDOG mentioned, the clear tone for me is the biggest pro for a multiscale. I don’t know if it applies for all multiscales, but the dingwall is awesome.
Adapting to the bigger scale was no problem.
As many have said… Tonality, clarity, brightness, tactile feedback you get from strings and even the body of the bass.
I went from a 4 straight to a 6 Multiscale, 37’'. BTB806MS, adapted quickly enough. Bass also punches way above it’s price tag.
And the way they “fan” across the board helps my wrist angles. Nothing like trying one and see how you adapt.