Having been a bass player for 19 years, and mostly having played 4-string instruments in that time, I hadn't really considered ever using a 6-string bass. I mostly saw extended range instruments as unnecessary and, if I'm honest, something of a show-off.
Bearing this in mind, when I dropped into a local music shop a year or so ago, I really only picked up the NTB-6 through idle curiosity, never seriously thinking I'd be taking it home with me!
The first thing that struck me was that the bass felt really 'organic'. The finish on it is oil and wax, rather than varnish or lacquer, and it allows the grain of the wood to be felt as well as seen. The neck of the bass runs right through the body, and is made from three pieces of mahogany, with strips of maple in between. The rosewood fingerboard has pearloid position markers that are visible from the front and the side, and is adorned with 24 jumbo frets. The body wings are made from Imbuya, an Indonesian hardwood which has a very distinctive grain. There are a few areas that could have done with a bit better finishing, but on the whole the woodworking is of a reasonably high standard. At this price, I think you can forgive a few minor imperfections.
The second thing I noticed was that this bass felt HUGE! If you've only ever played 4-string instruments, then this thing is a massive jump. Not only does it have an extra string on each side of the 4 you're used to (one lower, one higher) but it also has a 35" scale, compared to the 32-34" which is more common.
The NTB-6 is fitted with twin humbucking pickups, each with its own volume and tone controls. At the body end, the strings are held in place by 6 individual bridge saddles, which allow both top loading or through body stringing. Tuning is taken care of with 6 compact machine heads. All the hardware is finished in black and, while it isn't of the highest quality, it works perfectly well and feels solid enough. I've seen instruments at 3 times the price with hardware of similar quality.
It is possible to get a good range of sounds out of the NTB-6, despite the fact that it only has passive tone controls. It'll do reggae, jazz and rock equally well, and while it lacks the brightness to do Marcus Miller impersonations, it'll cover more or less anything you ask of it.
While this bass isn't on a par with some of the more expensive offerings out there, at less than £350 it punches well above its weight. I'd say you'd need to look in the £500 - £750 range to find anything substantially better. For the money, it can't be beaten.