You'll get a good vape with an ego, regardless of the brand. KGO, Ego, IGO, etc. If that and low resistance cartomizers don't work for you, you'll probably want to get a higher voltage device. You could always pick up a 5V box mod pretty cheap.
I have a 510 like you have and didn't mind it (it wasn't my all day vape). The biggest drawback to me was not being able to use low resistance cartomizers. That was the key for me. I like the boge 2.0 or the smoktek 1.7. The smoktek cartos hold more.
Very good infomation from swedishfish, I would suggest that you consider a mod like the Megalodon. It has a 18650 battery that should last all day and vape at 3.7v. Which is the same as the KGO, EGO etc, but also can take other battery's for different voltages. So by just changing out the battery's you can do 3.7v, 5v, 6v or 6.7v all in one mod & it's on sale now for a starter kit for $127.00. that includes 2 18650 battery's 5 LR cartos and a battery charger. Just about everything except juice.
I just bought one & I'm sitting here waiting for the battery's to charge so I can use my DON for the first time