This was delivered about 3 weeks ago, we have slept perfectly on it with no having to 'get used' to it period.
It's firm enough to support with a nice soft (but not too soft) top, we deliberately bought one like this as I enjoy the flatter surface.
We don't use a topper anymore, just a thin sheet as the bed is really comfortable.
We didn't bother heading into a store to try it as I did the online help thing which tells you which mattress suits you and then just read the reviews.
I am glad we opted for this mattress, lovely and comfy with plenty of support.
The delivery guys were great, polite and put the new mattress on the bed for me and they kept me well informed of delivery time.