I think you should read up on Exchange 2010. Microsoft have added support for SATA/SAS disks rather than relying on FC - something that's been improved since Exchange 2007.
So - even though it's a 64bit application - although 64bit capable hardware has been out for an age now - it offers huge storage savings.
Please provide information on 1) how it is bloated 2) how it is enormously inefficient - please go down to the database and transport layers if you must to help me understand and 3) please identify these standard features every other mail product has so a comparison can be made.
Overall a MASSIVE thumbs up to Exchange 2010. When 2007 RTM'd I and many found it lacking - 2010 is simply the best release of this product ever.