I test a lot of the legendaries (I don't have the new ones but I test the rest) and old ring perform like crap. Bracers are ok but once we get T20 2p the cd won't line up with CW so it will be useless, belt was ok too but I don't feel like this is actually helping the raid a lot, except on fight like Host where you don't have 4 healers watching the tanks.
I was about to stick with belt when I decided to test Prydaz. Prydaz provides more HPS than any other legendary (including Velen's) but this is only in ourselfs. But at the same time, all my heals were stronger cause of the amount of extra stats that Prydaz provides.
I was a guy who always hate Prydaz but at this point looks like it will be the higher overall HPS increase and the most consistent buff to all our heals (cause of the stats).
I was looking to test the new ring cause I love the SotF gamestyle but the T20 4p kinda kill it and also this ring have around 1400 less stats than any other 970 ring so you are starting with around 3% less healing. I don't think ring will do 9%+ to compensate the -3% and beat Prydaz or belt consistent healing.
SO for me atm it's Velen's + Prydaz BiS for raids. Belt + Prydaz BiS for dungeons (high M+ keys 15-20s+) except during Grievous week, I recommend shoulders and belt to run abundance build and snipe those nasty grievous debuffs