In terms of ranking up, Vanguard. Vanguard can be ranked fairly easily with all the ways to do it such as Patrols, Bounties and Strikes. Weekly Heroics and Nightfalls will give you +500 on completion and by completing both you could have +1000 which means you could easily rank up a level in a day. Overall Vanguard is more rewarding, the Vendor sports better gear for the field and leveling and has better weapons than the Crucible for the most part. Also completing tougher events such as a ROC Strike or Weekly Heroic could get you a Legendary Engram, Ship, or Exotic as a reward at a much higher rate than the Crucible. A great scenario would be you go on a Weekly Nightfall, as you go on your mission you encounter a Public Event and do that which gives you a Shard or Energy maybe x2. As you continue playing you get a few rare engram drops from enemies and maybe if extremely lucky get a legendary engram drop. After beating the boss you are rewarded with +500 reputation which lets say boosts you to Vanguard Rank 3, you also get maybe an Exotic, 2 Legendaries, +11 of Shards or Energy or maybe +11 Strange Coins. Then you go to the tower and open your Rank Up Vanguard Package and get a Legendary item from that and a Vanguard Commendation. If your lucky with the Cryptarch you have a chance at a Legendary from the rare or legendary engram drop. Then you can go and because you've achieved Rank 3 with the Vanguard you can buy anything from them you want as long as you have enough Vanguard Marks. Crucible ain't gonna give you any of that.