I'm undecided on Destiny.
I enjoyed the single player, but was rubbish on the multiplayer. But I'm not sure if that's just because I had rubbish weapons and unlocks compared to other folk.
I only actually played two games of multiplayer. One with a level 6 warlock, and one with a level 8 titan.
Actually, I played one more game with the level 8 titan but I'm trying to pretend that never happened. It started as 6-v-3 (I was one of the 3) and then one of my team-mates left. I don't care how good or bad you are, if you're playing an FPS with six people against two or three it's going to be a total whitewash.
I see the comparisons to Borderlands, now you mention it, and that's strange - because I really didn't like Borderlands (I played the first, but didn't get very far through it - never tried Borderlands 2) but I'm enjoying Destiny's campaign. :\
My best bet might be to leave it a few months, pick it up cheap, and stick mainly to the single player.