They don't sound as punchy as contemporary basses. The sound is more thudding than bright, since the hollow portions of the bass absorb some of the sound. It's not a bad sound, but is very different than you hear in most songs.

I haven't played the one in your listing, but have played other Hofner violin basses. Honestly, they're probably not the best for a beginner. The action (the distance between the strings and the fretboard) is sort of high, which makes it more difficult to press the strings against the fretboard. And basses with fixed bridges (bridges that bolt directly to the body, rather than attach to the end of the bass) are easier to keep in tune than ones like the Hofner.

The best thing you could do is go to a guitar store and test drive a bunch of different basses, since each one will have its own sound and feel. You'll be able to compare the violin bass side by side with solid-body ones and see which one feels more comfortable and natural in your hands. If you bought the Hofner and found it difficult to play, you'd probably be more inclined to give up. But if you made sure you found a bass that felt like it was made for you, you'd be able to learn and switch to a violin bass once you were comfortable with the fingering.

I'm in complete agreement about the violin basses looking cool, though. If they played and sounded as good as they looked, we'd see a lot more of them.