My observations so far (remember I’m not an audiophile):
1. When playing Atmos movie tracks I slightly prefer just using the ST5000 soundbar (SB) vs adding the 5.1 rear (non Atmos) surrounds. Of course, this is based on having Atmos settings on SB set up optimally for your listening space. Still a bit front heavy, but I felt the rears did not add appreciably to the experience.
2. On 5.1 tracks...the rear (non Atmos) surrounds do add significantly to the soundfield. By adding the Insignia non Atmos rears...I am pleased with the end result, as I did miss the rear input.
Atmos movies I’ve tested: Skyscraper, John Wick (#1), Everest and Goosebumps 2. Personally, I liked Skyscraper (overhead helicopter) and Everest: had to play in either Atmos or 5.1 (all spks)...couldn’t test Atmos to SB while utilizing 5.1 rears as my only Atmos copy is on iTunes and I wasn’t able to simultaneously output Atmos/5.1 (see earlier posts). While there were some good overhead effects on Goosebumps 2 (Vudu on Roku is capable of Atmos/5.1 output simultaneously, it didn’t WoW me. John Wick rain scene was OK but I didn’t feel immersed with rain from overhead on Atmos.
I also tested several Dolby Atmos demos on You Tube and I was definitely in the Atmos bubble.
My only regret is not being able to test ST5000 vs Samsung HW-N950 (with integrated Atmos rears), although it’s probably better that I couldn’t due to price difference of $600 when I ordered...no way for my budget at the time.