Ok, I removed my original post, and placed it on oneplus.net...
but since there is respons here as well, this was my message:
Ok, I made up my mind.
Although I love the 3 (coming from opo) and thought I could live without the extra battery, improved front cam and 821, I decided to return the 3. Like the darker colour of the 3t, and hated the idea that my new phone was second best. A little more battery is nice too (but when you hesitate: one day usage is easy on the 3, and dash charging is very, very fast and easy).
I have my rma-papers already, and will return my 3 in a few days.
After that it's waiting for my money, and hopefully I'll be able to order the 3t without again a 4 weeks delivery time
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udate: today I sent back my op3... he will be missed!
let's hope all goes well and there will be enough stock 64gb's