I'm a honeycrisp fanatic (and it's a good balance of sweet/tart for me). This is the first I've heard of Sweetango, I don't think I've seen them in the grocery stores. Will be keeping my eyes peeled.
Unlike many other apple varieties these days, SweeTango are only available in traditional "apple season" (Autumn months through November in the USA). I've long been a fan of HoneyCrisp, so I tried SweeTango, and while it was quite good, I still prefer HoneyCrisp. I had a similar experience with Cosmic Crisp--not as good as HoneyCrisp, but nice for some variety.