Yes, the material has aged, but let yourself go and enter the world of Byston Well, you won't regret it. Aura Battler Dunbine is IMHO one of the strongest works Tomino (of Mobile Suit Gundam fame) ever did. In fact, it has two strength even the original Gundam and its most glorious sequel, Z-Gundam, don't have.
First of all, the heroes come from contemporary (well, early 80's) earth (Upper Earth, as Byston Well dwellers call it), which allows Tomino to introduce such rare things in anime as ethnic tension, or robot fighting within contemporary cities (a unique case in Tomino's real robot production). But most of all, Tomino has tried to create a fantasy world, Byston Well, with its own races, and a real sense of wonder, which almost equals the best fantasy novelists. That's a unique trait, that sets this anime apart from all the other robot stuff. I could also speak about the characters relations, as complex and tragic as those of Z-Gundam, the absence of the comic antics that have ruined some other Tomino's series (like ZZ-Gundam or Heavy Metal L-Gaim), or the original mecha design which adds to the identity of Byston Well as a fantasy universe. But you already see my point: Dunbine is a real masterpiece among the real robot animes of the early 80's (and that says a lot, since the genre includes such classics as Macross, Votoms, or Z-Gundam).
One last thing: many of you will link the whole fantasy plus mecha thing to the famous Visions of Escaflowne series, so I'll tell my opinion about it. That Dunbine was used as an inspiration to create Escaflowne is a given. But I think Escaflawne failed to emulate Dunbine, because the world and the characters of Dunbine are (much) more fleshed out than those of Escaflowne.