I've taken, this year:

2 x suite upgrades, neither of which I've used. One expired ages ago, the other in 3 days I think.
1 x lounge access that I may or may not have used once.
Rest were 10k bonus points. £40-£50 value perhaps, but more useful for me in the long run.

Might of been tempted by a food / beverage reward. Last night's stay in a HI had fish & chips for £18 (around £7 from my local chip shop) with a £7 tray charge. That put me right off ordering anything (same £7 charge even if I ordered a bowl of chips / fries for £4), although a £15 offset might have made things a little more palatable.
Have to admit, last time I stayed at Heathrow, I walked a few minutes to McDonalds rather than pay room service prices.

Took a 10k milestone reward earlier today and the points were in my account as soon as I refreshed the page.