Since both are styled and scaled on the Parabelum pistol, Ermas look similar, but only at a glance.
Stoeger owned the legal rights to the brand name
Luger at that time in the U.S., so in a sort of technical way these are Lugers. However, these are blowback system guns with a toggle that jumps up and down, basically for show. They contain many stamped/pressed steel parts. Two versions were made; the steel frame ones, I think, are the more desirable in a small collectors' niche they have, and I think shooters prefer them, as well. Their operational reputation, however, is about the same as the earlier, Zamak action Ermas. If you're buying it to shoot, and it actually shoots dependably, then enjoy! I can see how it might be a minor collector/investment--but in that case, just keep it in the box. My theory is, if you don't try to shoot it, it can't display issues or fail. Then your conscience can be clear when you cash in when value plateaus.
With the nice box and original stuff, I'd say top retail for it as a collectible is somewhat North of $300. There's a halfway decent .22 Stoeger Luger shooter that's been camped out on Gunbroker for a couple of rounds, starting at $200. So, we are operating at about a 1/5 scale, price-wise, of original Lugers (Sorry, Ron).