I'm a professional violinist and have used many electric violins over the years. However a 6-string instrument is rather a speciality and needs to offer not only good sound and build quality, but also ease of use.
The Fidelius HK-6 offers all of this: The key thing for me is that care has been taken in the spacing of the strings and the curvature of the fingerboard, making this instrument far more playable than other 6-string violins I have tried.
Perhaps the beetle design might take some getting used to, and may not be to everyone's taste, but I rather like it, and absolutely love the inlaid wood which gives a very striking appearance.
The pickup quality seems excellent, and I have no issues with the sound the instrument produces: I use it mostly for live-looped arrangements, but will also be using it as a solo instrument in 2021, with some major concert appearances planned when - and if - the current pandemic subsides and life returns more towards normality!
A 6-string electric violin is definitely not for everyone, and I would only suggest it for those players who really want to explore the additional range it offers. It is very different o play than a standard 4-string instrument, but it can offer some unusual and interesting opportunities for your music making!
If you want to go 6-string I would not hesitate to recommend this instrument.