Apparently, there is free data recovery via within the first 90 days of buying a drobo, which seems pretty safe as it is unlikely to fail within the first 3 months.
Also for an extra fee "cheaper" than the cost of recovery, you can buy extended protection for up to 3 years. I'd be curious to know the cost of the extended care and their suggested cost of recovery services.
http://www.drobo.com/storage-products/drobo-care/