Julio & AB are the only two complete receivers in the NFL. I'd argue that they are the only ones who can do everything at the receiver position, and do it exceptionally well. Some of the others may seem close, but I think those two are far and away the best two receivers in the game right now and are in a tier of their own. Honestly, except for Calvin Johnson in 2012, the way they've both played in the last two years are probably the best we've seen in a long time.
At the current pace they're on, they will basically be tied for 3rd/4th (Julio leads by 0.2 yards/game, lol) at the end of the year with 1820+ receiving yards, only behind Rice '95 (1848) and Megatron '12 (1964). Brown's is probably more impressive, as he played several games with terrible QBs (in 5 basically full games with Ben, he averages 160 yards/game... even if you take out his insane 284 yard game against Oakland, it's 140/game) and definitely has a chance to break the record. These are two very good receivers in the heights of their careers right now, and I really don't think a third name should be mentioned with them when it comes to the greatest WR right now.