Sergey,
Basically the advantages are ones related to granularity of control. There can also be some performance advantages as well.
This is not a free lunch however, and should be planned as carefully as possible. There are some down sides like the monitoring of integrations is not as straight forward.
There are considerations like how to handle ‘global’ objects (Table, Variants, procs, etc) – much of that seems to be taken care of with the Master Site concept in 5.6 Cloverleaf(R).
There are also considerations as to the architecture of the sites to best fit your needs.
I would say you are at a place where doing this thinking makes sense.
This is a topic not easily discussed in a forum context. The last time I went through this thought process with someone it took around 30 minutes of conversation.
If you will be at this year’s User Conference I can spend some time with you.
Otherwise, email me and maybe we can discuss this off line.
email: jim.kosloskey@jim-kosloskey.com 29+ years Cloverleaf, 59 years IT - old fart.