The nice thing about the Dune is, you can give fatbiking a taste for a relatively small price, but it’s fantastically upgradable. And even if the worst happens and it breaks in 366 days and Calibre don’t help, all the bits will fit directly to any other decent modern fatbike. (mine is one of the first so it’s out of warranty, it’s had the shit kicked out of it frankly and hasn’t winced but if it does break tomorrow, I’ve had far more than my money’s worth from it and I’ll order a carbon frameset off ebay to replace it without any stress. I’d honestly say it’s one of the best conceived budget bikes ever made.
But if you know you want to get right into it, it probably makes sense to spend more. Mine’s worked out good value but only because I really worked at it. Alpkit Vir Fortis?