I researched Spartan a while back, did not find anything good about them, very generic and simple. As far as I could discover, they don't manufacture anything but are a VAR (Value Added Reseller) buying from primary OEM's in China who make a variety of specs for VARS to choose from. Think AIMS being fairly similar but AIMS has a dedicated company and actually adding value & facility to equipment and backing it.
Unfortunately Samlex America does not offer a 48VDC input model for North America... They intend to release such in 2020 with the next family of Inverter/Chargers.
As for "Junk", stick to Tier-1 products like OutBack, Schneider, Victron and the junk factor isn't there but the $$ is.
Tier-2 imported Quality products are cheaper an still meet specs and certifications and are backed with a credible network.
Tier-3 Value products, you take your chances... EP-Ever or Renogy ? Yiyen, Sigineer… some are better and some are worse. I would never personally buy anything Renogy - it's toss away stuff. but EP-Ever is better as is Yiyen (an OEM) & Sigineer (an OEM & VAR).
Bottom line, depends on your bottom line and the depth of your budget and how much risk you are willing to accept if your spending small... It's NOT a knock at all BTW, we all have to live within a budget and often that means a set of compromises which we gauge our risks & potentials.