I am blown away by the quality of this instrument. At the price range of 200 - 250 euros, this is undoubtedly one of the best choices you can make, whether you're casually looking for your next bass to have fun/jam/gig with, or you want to purchase your very first bass!
Build Quality:
The glossy finish on the body is extremely well done, the knobs feel sturdy and easy to rotate, the jack is very tight and holds the cable well, and the neck has an absolutely lovely finish. The fretboard is nice, doesn't feel dry, and the factory D'Addario strings are very solid. I didn't replace them.
I did proceed with some slight truss rod adjustment and lowered the action, just to make the instrument even more playable. It worked perfectly!
The only thing I wanna mention as a slight downside is that the metal plate they used that holds the knobs and jack feels kinda cheap. You can see some leftover "stains" when you lightly touch it and remove your finger. That, however, is expected quality assurance wise. You can't have such an awesome instrument for this price and not expect any compromises. Therefore, this won't affect the rating.
Comfort:
The Harley Benton MV-4JB is extremely comfortable to play.
The neck feels very very smooth and it has the perfect width. It's ideal whether you wanna play some lines, fills, chords, arpeggios, anything. It is a breeze to just move your left hand around the fretboard, even on the higher frets, and play whatever phrase you wanna. It is a gem.
The only thing that's not-so-comfortable is that after playing while standing for a bit (say around an hour) you might start to feel some stress put on your shoulder. The headstock seems average sized for a jazz bass, but that could just be me. It could be larger, I didn't compare.
Pickups:
The HBZ custom pickups are actually solid and produce a nice, warm, slightly punchy sound, I am very very satisfied with them! Now yes, if you want the most high-end sound possible, you'll probably replace them in the long run. In my humble opinion, though, it's not necessary. They sound punchy enough for the average joe, and unless you plan to play for metallica, a lot of listeners probably won't tell the difference between them and better pickups (the lower frequencies also help with that, haha). I did a gig with them for a local show, where I used the venue's full rig of course. It sounded so nice I was blown away a 200+ euro bass could produce that sound.
Now, I know that the main factor that affects your tone, guitar or bass, is the cabinet's speaker (impulse response), and to another extent the head amp. I am not saying the pickups produce THAT sound I had, I'm just saying if you're looking to gig with this thing without doing any upgrades, you ABSOLUTELY CAN! The not-so-flashy HBZ pickups will be just fine, I promise :) Just replace them when something seems off with them.
Sound:
As was hinted in the pickups section, the sound is phenomenal. Warm, full, a little bit punchy, it has it all for what you're buying. For my clean tone I mainly use Guitar Rig 7's "Super Bass" profile, and modify it to my liking. For my distortion bass sound, even though the pickups were not really designed for such sound profile, I use Bogren's Trivium Bassknob head amp with some other bass IR's (Komposition101, Tone3000), and just crank up the gain, haha. The sound is obviously not Dingwall bass level, but it is alright with some tweaking and other plugins. I had fun with it still.
But yeah, the clean tones sounded just perfect, and I didn't get any annoying noise even on higher decibels and gain levels. That was so cool!
Overall:
Just buy this bass.