I have Joon and his costume, both versions maxed. Regrettably, he has no emblems as they are allocated to Rana+20 (I was after the mana bonus node), Drake Fong+I6 (formerly +19 but stripped him of emblems to give it to Rana since I don’t think the +4% mana bonus on the 20th node matter to much for Drake), Wilbur+20, Li Xiu+19 with MCB, Bauchan+20 and two Bjorns each at +10.
I also have a 2nd Joon, both original and costume versions at 3/70. I deferred using darts on him as I am hesitant using them on dupes, unless a very good one. I, too, am leveling my Uraeus, still currently on the second tier of ascension as I am slow leveling the guy but he will get maxed as I have 25 poison darts in my inventory. He will be my 8th maxed holy legendary, who will get fully emblemed, or close to it, as I have 972 sorcerer emblems plus the ones with my Skittleskull+19 with MCB, who I plan to strip of emblems in favor of Uraeus. He will be my heavily emblemed hero in my 2nd monoyellow sniper team with 2nd Gazelle+6, costumed Joon, Poseidon+7 and Lady Woolerton+18.
What I love about Uraeus is that he has no skill that will buff his allies as this will get nullified with Gazelle. His Element Link only summons minions to all holy allies, which is ideal for my 2nd monoyellow. My first monoyellow is an AOE team composed of 1st Gazelle+7, Drake+16, Onatel+20, Rana+20 and Gull+19.
Both have their uses. Joon blinds as he snipes at fast mana while Ureaus bypasses minion while sniping at average mana, leaving sand DOT to all enemies with minions as well as summoning minions to all holy allies. With limited darts, the reckoning point is the availability of emblems.