Hi JohnOH,
Just to clarify … the OMF Serenity doesn’t have any 4 lb memory foam. All the memory foam it uses is either 5 lb or 8 lb. You can see more details about its construction in post #2 here and for most people it would feel quite different.
Having said that … you certainly made a good value choice and I’m looking forward to your feedback about how it feels for you when you receive it.
I don’t think any concern I have would be with its strength but with your weight impressing the foam over time into the gaps. Now that you have it though … I would personally leave it as it is because I would tend to prefer a more breathable base under the mattress (you can read more about this in post #10 here).
OK … I completely misunderstood … that makes a lot more sense
You’re very welcome … and congratulations on your new mattress
Phoenix