Now that I've ported my number and am using Voipo as my only line I've noticed this issue more and more.

It's the delay between the two parties .. somewhere in the .5-1 second range. Sounds like a CB radio or something, waiting for the other party to stop talking so you can start.

Is it worth submitting a ticket for this issue, or is that the nature of voip communications?

(I've tested my ISP with various online testing .. all grades usually "green".)