I've owned a couple of Marusczyk's, and they're ok, if you pimp it out with decent Hipsot hardware, then it'll be on the way. But I didn't really get the feeling from those basses that they're doing anything particularly special.
Fender, yeah fine, their QC has gotten WAY better over the last 5 years or so. But I find their new basses just a little bit uninspiring, I couldn't tell you why.
Sandberg, similar deal, clearly got a lot going for them, lots of love, but they have just never done anything for me really.
Where I settled was Lakland, in my opinion, their Skylines are on-par with US Fender stuff, and if you have the budget to move into their US Custom stuff, the necks are wonderful as well as a full pallet of custom options. You said you've checked them before, but was that one of their active models? Worth bearing in mind that they do make straight P and J passive models too. Still a family-run company too.
I think the only place I'd go after Lakland would be G&L, they seem to be very decent for the price, even if they are a mild deviation from the 'Fender' aesthetic.
Si