In all honesty, sometimes the thing does run out of memory...
I think a lot of people could visualize the danger in the device having only 256 MB when we all first found out about it (long before we knew ip4 had 512). It's sort of like the danger of ATT's 2 GB cap. Yeah it probably works OK today, but with usages being unlocked (multitasking, more powerful games, MMOs), you can see how 256 can quickly become very, very limited.
Let's see what iOS4 gives us - Apple knows its software well and maybe they'll give us a way to keep how snappy this device is, even with multitasking. However, I think it's natural for some folks to be skeptical...
ip4 drives less pixels and the size of the screen doesn't lend it to as much content being passed through it as the iPad. So why does it get twice the memory? A lot of what our gut tells us is Apple was simply being cheap, or even worse - short-sighted. I hope we're wrong, because it really would suck to get the experience of the device take a hit when multiple things are up and running.
The safari reloading can be quite annoying, too. Perhaps almost as annoying as Apple's lack of response for this feedback from their customers.
My iPad tends to "flush" (ie: dump) multitasked processes in its jailbreak state now and then - something my iPhone gen 1 doesn't yet do with the same apps running simultaneously. It's my hope that this is an artefact of implementation shortcomings of jailbreak-Backgrounder instead of the obvious - a device running "huger" apps on not so much "huger" memory,