I usually renew Amb anually - the major benefit is rolling over my IHG Diamond status, went through fine again this year despite the initial 'inspection scare' everyone went through! The detail already provided above is entirely accurate, I have always found value in renewing due to the following:

- 4pm late checkout
- 2-1 weekend voucher - despite the markup over regular rate, I have always found value in these redemptions year after year.
- Upgrade category is fine - several properties flood the category rates so don't expect anything major here, but can be a nice touch with a better view here and there.

Rest of the benefits are so-so - but I've always found the renewal price worth it for the above alone.