AFAIK There's two issues with the VR£ buttons. One happens if you let your finger off the button when it's fully compressed, it can spirng out so fast that it over-rides the circlip (older models) or U-clip (newer models), so you need to keep your finger on the button as you release it. Secoind problem, which I've only heard about, is that water can get under the plastic through a small split in the moulding and corrodes the magnet which expands and cracks open the button, it will then jam in the body of the VR£.
I know Delta P do replacement spring kits, I got one for free ages ago and luckily haven't had to use it so far. I did have the buttons fly out a few times until I got the hang of it.
But hey, what do you expect for £800?
Still a great computer.
Bet mine fXcks up this weekend now...