EMC DASD vs. IBM DASD and MIMIX for 24/7 operation

Gang,

First, have any of you hooked up EMC DASD to an iSeries?   If so, good
news/bad news?
Second, how do you like it vs IBM's DASD?
Third, supposedly EMC has a way to "split" or "mirror" or some such
their DASD to allow a site to have a similar function like what MIMIX
and MIMIX Lite can perform?   Yes/No?
Any MIMIX users out there that have used it between iSeries LPARs?  
Good News/Bad News?

Problem statement:  I'm looking for a way to reduce or eliminate my
current 5-6 hour backup and 5-6 hour reorg windows so I don't impact my
e-commerce and other applications as much or at all.   

Alternatives considering:  

- Faster tape drive, like an IBM 3581 - Might reduce my current window
for backups in half; does nothing for reorg window
- Add fourth LPAR with MIMIX between it and our Production LPAR and
backup and reorg jobs that make the environments for applications
essentially 24/7 operation, i.e. backup from 4th LPAR which is the MIMIX
"mirrored" LPAR from Production.   Since I also have "blade servers"
under the LPARs, I probably would need to use the MIXIX for Windoz
solution as well to keep the 5 blades in each LPAR synced.  For reorgs,
switch back and forth between LPARs and reorg the one that is not
"online" at the time.   Resync LPARs after backups and reorgs.
- Use EMC DASD if it has a good or better solution than adding another
LPAR and MIMIX
- Don't install 4th LPAR but instead use our 2nd LPAR used for testing
of new releases of application software and for our ODS/DW (Operational
Data Store/Data Warehouse) Project. Install MIMIX between it and the
Production (1st) LPAR, add more DASD and perhaps turn on 4th Processor
if necessary.  I understand this would work even though application
levels might be different as MIMIX doesn't care about application
levels, only data changes and the application's file structure RARELY
changes.  
- Just use SAVE WHILE IN USE function of V5R2 or V5R3
- Turn on 4th Processor if necessary for reorgs or whatever needs more
power
- Is there a better mousetrap with V5R4 due out soon?      

Thanks in advance,

Dave Odom
Arizona