I tested out the photo merge panorama feature in Lightroom 6/CC today, and I must say I’m pretty impressed with the outcome! The images I had were taken in Kerala, and not taken with a panorama in mind. I just happened to be shooting every angle that would fit in my frame of the view that was in front of me, and when doing this panorama, the images were not aligned properly at all. Lightroom did a fantastic job of auto-aligning it and making it look seamless and still giving me a decent photo quality!
Unfortunately I can’t say the same for the HDR feature just yet. The photos I used gave me an image that I could have easily produced in Lightroom 5 with just one image using the sliders. However, it could just be the images that I used. I will try it a few more times with different images before I come to a conclusion on this one.