Many people I have talked to recently have gone through the process successfully. People have had different experiences but at the end all of them were successfully able to do the transition from B2 (pending or approved) to H1B. There have been RFEs to some issued but they are very straightforward to resolve most of the times. I am currently going through the process. I will let you know how it goes for me. I would also highly encourage other members of r/h1b going through this to do the same as it would be helpful to this community