The slim tanks at IBTanked would look the best on an Ego, if aesthetics are important to you. You can order a clear tube with metal endcaps for under $25. As Ocelot mentioned, the acrylic caps also offered are apparently susceptable to some of the caustic juices. The stainless steel caps come in different colors now, also.
If you don't mind that your setup looks top heavy, the other pyrex tanks will work also. With the Triple V tanks at Valley View, I'd only recommend them if you order the metal endcaps. The default grommets are silicone, and although Ray states that they would be safe with caustic juices, they must be filled with a blunt needle. The grommets fit so tightly that you might struggle changing out cartos, too.
The Phiniacs are one of the best tanks available, but they only come in one diameter, which may look top heavy on an Ego.
View attachment 142591
IBTanked on a Twist
View attachment 142595
IBTanked and a Phiniac on Provari's
View attachment 142593
IBTanked on my Silver Bullet, Provari, and BB
View attachment 142594
Valley View Vapes 7ml on my BB