I've seen both cards, and IMO armed looks cooler.
You also have to time Horus, because they give no specific time to activate Armed's effect, so you can activate it at any time you choose. And all you ahve to do is slip some blue eyes white dragons into your deck to make Armed as deadly as he can be. Which I have done with my armed dragon deck, and I almost always pull them thanks to get out all I need early. Or better yet, put a perfectly ultimate Great moth in there just in case. Something I can also do. And I speak from experience that people usually don't use Equip spells anymore. So it is actually a better chance for me to pull my monsters needed for Armed's effect than it is for the Horus user to get an equip spell.
You seem to be under teh impression that that measely 200 point difference actually makes a difference. As I said earlier, attack strength alone isn't teh winning force, effect is. And monsters win duels, not magic. Horus stops magic, and armed stops monsters. So in terms of effect, Armed is much more devastating. Good duelists carry the duel with their monsters. NOt their magics. The most devastating duelists I fought rescently I don't recall playing a single magic besides Pot of greed. What I do recall is Jinzo, Vampire Lord, tribe infecting virus, etc. MOnsters carry the duel. Not hte magics. Magic negation? Big deal. Mosnter destruction? You better whatch out.
ANd your still adding extra cards to the equation. So how about I do this then: Summone exiled force, tribute him and goodbye Horus. Not JInzo, SoDM, or even Horus himself can stop that.
According to the summoning effect of the both the first forms, Armed is much easier to handle. Level 4 Horus has to kill something, while all level 3 armed has to do is live. an if you get him from a Masked Dragon, then it's all teh easier. However, in horus's case, a 16 hundred attack monster doesn't kill much nowadays. :\