AIX

Can anybody help me in giving some quick tips... on the updates on this new version AIX V5.3??

There is also a Redbook titled AIX 5.3 Differences Guide, which one can download from:
IBM Redbooks | AIX 5L Differences Guide Version 5.3 Addendum

Might as well read up on AIX 6, as AIX 5.3 is near its end .

The following from wikipedia gives you a quick view of feature added in each version. I hope it will easy to make out the difference from this.

POWER/PowerPC releases
* AIX 6.1, November 9, 2007
o Workload Partitions
o Live Application Mobility
o Role Based Access Control RBAC
o AIX Security Expert hardening tool
o Trusted AIX
o Encrypting JFS2 filesystem
o Trusted Execution
o Concurrent Kernel Maintenance
o Kernel exploitation of POWER6 storage keys
o probevue dynamic tracing
o Systems Director Console for AIX
o Integrated filesystem snapshot
o Partition mobility on POWER6
* AIX 5L 5.3, August 13, 2004
o NFS Version 4 support
o Advanced Accounting
o Virtual SCSI
o Virtual Ethernet
o Simultaneous multithreading (SMT) support
o Micro-Partitioning support
o POWER5 support
o JFS2 quota support
o JFS2 filesystem shrink support
* AIX 5L 5.2, October 18, 2002
o Introduced support for the IBM BladeCenter JS20 with the PowerPC 970.
o Minimum level required for POWER5 hardware
o Support for MPIO Fibre Channel disks
o iSCSI Initiator software
o Dynamic LPAR support
* AIX 5L 5.1, May 4,2001
o Introduced support for the IA-64 architecture, although this never went beyond beta,[1]
o Minimum level required for POWER4 hardware and the last release that supported Micro Channel architecture
o Introduction of 64-bit kernel, installed but not activated by default
o JFS2
o introduced Logical Partitioning on POWER4
o The L stands for Linux affinity
o Trusted Computing Base (TCB)

* AIX 4.3.3, September 17,1999
o Added online backup function
o Workload Management (WLM)