OnePlus 6T doesn't have much difference when compared with OnePlus 6. The major changes are the lack of headphone jack and presence of in-display fingerprint scanner with big battery as well. And it comes with Android 9 pie out of the box, with smaller water drop notch.
The fingerprint scanner and small notch gives a futuristic look and feel to the phone. It looks and feels premium because of glass finish and it comes with gorilla Glass 6 protection and it is built like a tank. It looks same as that of 6 from the backside. But sadly the fingerprint scanner is not present here. The performance of this phone is gorgeous, it performs better than Samsung Note 9 and comes close to iPhone XS because of the Oxygen OS software. The software is one of the positive because of good timely updates and gives extra high speed performance. The display is too Great but not great as that of LG G7+ which comes around same price. The cameras are same as that of OnePlus 5T and 6. Audio is great too. Cameras are great and it can shoot great photos and videos without any shake. And selfies are good too. Lack of headphone jack is a big negative and it's deal-breaker for many music lovers like me. But there's a solution for that is included in the box and that's great. The phone comes with big battery than OnePlus 6. Which supports powerful and speedy dash charging and Super fast dash charger is also included in the box.
Overall the phone is a great deal for the price. If you have a OnePlus 6, no need to upgrade because of tiny changes. This is truly a great deal and Go for it.