I switched from the OnePlus 5, not the newer T version.
The main things I miss are:
1) the instant mute slider on the left of the phone
2) the better cameras. If OP5 was a 8, the razer is a 6 out of 10. Sometimes it shoots a 7-8 pic but things have got to be just right. (So I have hope that one day it will be vastly improved over the pixel camera apk)
3) the weight being lighter
4) the dark black's of amoled
5) the headphone jack. Dongles suck.
6) the front finger scanner. The Razer's is ok but you have to push it first to turn the phone on and then it scans.
What makes it totally worth it for me are:
1) the screen. It makes everyone jealous and rightfully so. It seems much faster than other Snapdragon 835 even the pixel 2xl, which my friend bought, just because the fast refresh. Clarity is fantastic. The brightness is not the worst like some people make it out to be and outdoors it seemed close to the pixel 2xl when my friends and I were doing phone wars.
2) the speakers are the best. PERIOD
3) expandability is nice but I honestly haven't used it yet
4) on 3D/cardboard it simply is the best experience I have had. The 120hz refresh didn't get me sick like on the OP5, pixel, etc phones that have 60hz. Now if we could only get daydream working. Razer missed an opportunity with being the best daydream experience on any phone. Isn't this supposed to be a gamers phone?
In summary, when I tried the OnePlus 5 just yesterday it felt slow and stuttery because of 60hz animations and syncing. He'll the Pixel 2 XL feels slow and stutters to my eye too now that I'm using the 120hz refresh. I'm much happier with the Razer over the OP5 bottom line. But take the other person's advice and try it before you buy it. These are my own findings and your needs and wants will most likely be different than mine.