I've heard horror stories about Peanut Plugs, but many people also seem to use them without problem. I believe the Osram issues you refer to are really just in the context of users with Xiaomi devices, where the "original" model is known to work well for those devices while the newer "-A" model may cause them to fall off the network (a quirk unique to the not-quite-standard Xiaomi devices, which you can ignore if you have none).
For Ikea Trådfri: the outlets do indeed seem to weak in my (and many others') experience, but that's not necessarily bad. My devices just don't appear to choose them as repeaters as often as other devices, but some still do, and it would work to extend both the range and capacity of your mesh if needed. But I don't really like them because they're bulky and a bit ugly to me eyes. However, the Trådfri USB repeater works well for me in terms of attracting more devices, and it's pretty small (about the size of a Kindle charger if that's a useful reference) and easy to power (it's just USB). But of course, if you want a smart plug too, you won't get one out of that.
I do like the SmartThings outlets, even though they are/were expensive. But a bigger problem now might be finding them: they seem to be out of stock in most (all?) places. If you can find them, I'm a fan. Nothing on my network is a more attractive repeater except my Xbee, which is another option if you wanted to explore that route (but there is a DIY aspect to this). I should note that I checked my routes again right before I wrote this, and the Trådfri repeater seems to be attracting a lot of devices, too--and I actually see fewer on the ST plug, though I did just (barely) move it a couple days ago, so my routes may still be in flux.
I no longer have any of the Centralite outlets, but that manufacturer has a good reputation, so I'd probably trust them. (I did have the old square Centralite outlet, sold as a SmartThings otulet, whose Zigbee portion is probably identical to the famous square Iris v2 plugs--also not a bad idea if you can find one since they have a built in Z-Wave repeater too, but it must be paired separately, and some people have problems with those, likely dependent on firmware versions, which you can no longer update with Iris being long gone.)
If I had to risk it on something new, I'd be curious to try either the Hue smart outlet (small, appealing form factor--though the smaller, rectangular CentraLite also is) or the Innr outlet (a 2-pack is currently selling for $35, so not a bad price). But I don't like recommending things I've never tried.