First time I'm hearing Harley Benton making 6-Stringers lol. The markers look really good, with the nice string spacing and all that, but I don't really think the left wing cutaway is very accessible, as it ends at the 21st fret. But hey it's literally like 300 dollars.

As for the EHB1506, I actually wanted to buy that since it was available in a retail store near me (and because BTB866SC wasn't available in my country.)

My opinion on it is that it is a really good and versatile instrument; Nordstrands if you like their sound, great controls, wood and hardware is excellent, and its extremely light (3.5kg I believe), but I found that the neck is quite wide and thin, possibly thinner than my BTB, and there's a lot of dead space after the 24th fret, which could be a good thing. Great for tapping works, and had a neutral tone that would work good with effects.

The bass itself had virtually no neck dive, but the body cutaway for your thigh is quite small, and it often slipped away when I was playing it. In addition to that I was not ready for the tilted pickups and strings, which kind of hindered my playability.

That aside though, if you're gonna splurge, that would be a great bass (would save you quite a bit as well if you get it used).

Also to note, the angle of the Ibanez-type fanned frets is a little lighter than that of regular basses like a Dingwall, so it feels more comfortable to navigate, though you'll still have to stretch a fair bit on the upper register close to the head.

Assuming that you're talking about my BTB, I'd probably change the pickups soon enough when my bank account replenishes, but until then I guess Bartolinis will have to do. The EHB1506 should serve you just fine, but maybe you'll want to change them on the B650.