I never owned the first version of these, so cannot compare on comfort.
I really agonized over getting the Sleepbuds. At $329CDN, it's pricey for an uber-niche product. At this price, it had better be perfect—or darned close. If it weren't for the 90 day trial I never would have picked these up.
I had no complaints on the overall package. The charging case, the way the buds click in, the app experience were all good. I never had a disconnect or other software issue.
However ...
I also found these not very comfortable. About halfway through the night, I could feel them enough that it actually made sleeping more difficult. In the morning, I could still feel them in my ears even hours after removing them. I would describe this as similar to the feeling after wearing foam earplugs—which I dislike. It didn't seem to have anything to do with the StayHears, just the shape of the actual bud. Side sleeping just made it worse.
My right ear was in-between sizes for the StayHears. Bose needs to include more tips. Even Anker is providing 8 or 9 tips with some of their headphones.
Comfort issues aside, there are a few other things which fall under what I call the "Complicated Solution Enhancer".
Bose calls it "Noise Masking". To me, it's basically a set of regular ear buds where the sound just covers up any outside noise. I found these to not mask very well. I could hear my partner snore (and she's not very loud), the airplanes, traffic, etc ... I had to bump up the volume above their 'warning' limit.
I have a pair of JVC Secure Fits (HA-EC10-B). They have the curved rubbery bit that goes behind your ears. Yes—they do stick out a bit, but nothing dramatic. They won't fall out overnight. They don't sound quite as immersive as the Sleepbuds, but they are close-ish. Nothing to charge, update or fuss with. Cost? $17CDN.
Ironically, I think the biggest competitor to the Sleepbuds is another Bose product—the QC20. I've been using these for years, and wear them through the night. Granted, side sleeping can be an issue, but I've found a way to position my head so they don't press into my ears. I have an app on my iPhone that plays pink noise. My GF made a nifty felt pouch that holds my phone on the headboard.
I've processed my return to Bose, which was a PITA as their only store in the Toronto area is now closed. The return had to be manually processed through their US office, and I'll be mailed a refund cheque ... how 1990s.