I went from the v30 to the 6t.
Pros: bigger screen 6.0-6.41(it does youtube HDR) , much more fast in terms of responsiveness,better battery life, way faster charging with oem charger(17%-100%)about an hour it flies. Finger print scanner is legit, face recognition is instant. 300 dollars off if you have a qualifying phone to trade in. Android 9 pie.comes with protecting case and screen protector, usb-c-3.5mm dongle. Wifi has better range.
Cons: no physical 3.5mm jack, speaker quality/volume not as good/loud, camera(s) , only a 1080 full HD/HDR compared to (V30 has quad HD/HDR).No SD slot for memory expansion. I have about 115 GB left after loading all my apps. My felling is the 115 GB won't be enough storage on the long run?
Overall I'm super impressed with the op6t good quality for sure!