No more SIS in MS Exchange 2010

Ferris analyst Bob Spurzem covers news around MS-Exchange. In this entry he hightlights that MS Exchange 2010 has removed the Single-Instance-Storage (SIS):
One of the lesser-known changes to Exchange 2010 is the removal of single instance storage (SIS). The reason for this is related to an architectural change, disk I/O performance, and the availability of cheap disk.
There tends to be a trade-off between better disk I/O performance and reduced storage capacity. Architecturally, Exchange 2010 introduces a new per-mailbox table structure that replaces the original per-database table structure. The original per-database table structure was optimized for SIS, but disk I/O suffered. The new per-mailbox table structure improves disk I/O, but without SIS.
In place of SIS, Exchange 2010 uses compression. Only large, redundant attachments files truly benefit from SIS; otherwise, compression delivers roughly the same volume of data as SIS."
Well MS sales people always had claimed (never backed by figures from real deployments) that SIS was a space saving advantage over Domino's one-man-one- vote database approach. Guess they learned the scalability lesson the hard way. Now if you want SIS for attachments and design compression and data compression - Domino is your answer.