I have migrated to one plus two from an older Samsung Galaxy grand Quatro. Overall I am enjoying the new phone. But I did find some issues.
It doesn't ship with a headset. For now I am using the headset of my previous phone.
It doesn't have fm. I used to use my earlier phone to listen to fm while driving. I don't have this capability anymore.
When I connected the phone to laptop today it didn't start charging. Towards the end of the day I looked at the battery details page to realize that it is not charging. Disconnecting and reconnecting the cable didn't help. Finally I restarted the device. Then it started charging. I could not figure out why this happened. Probably it is a software bug which will get fixed later.
The phone comes with a single cable. Thus one has to keep carrying it around. My earlier phone came with two cables. One with a wall socket adapter and other for pc connection. Having two cables I think is useful. This seems to be a cost cutting exercise. However official USB type c cables from one plus are out of stock on amazon. So getting an official spare isn't easy at this time.
Btw the phone is really fast and worth the money.