I think it struggles on the older devices, they have 25% of the RAM of the iPhone 4.

It's variable on my iPhone 3G. It's so slow at times I feel like throwing it at the wall.

I wish my iPhone 4 would hurry up and arrive.

When it does - could you send it to me ?

It does get painfully slow at times - I've been trying to sell it for ages (need the money more than an iPod), and aside from getting spam from the same person on Gumtree, no-one is interested in it...