Well RDS V/S HTTP.

Client side installation is less complex.
Only http port needs to be open on Server.
Top most reason, client is already using that, so cant help it. Have to 
use it.

Example would be.

Say if the information being sent is not a straight recordset and secondly 
you need a way to communicate the error info to client whether the desired 
action was performed without an error or not.

another example.

Client Info.
Client Address
Client Commodity listing
.
.
so on
+
IsError
IsDBError 

I hope this time I made my self clear about my requirement.

And ofcourse there are n..number of ways to do the same thing but for some 
reason or the other you have onehas to go a particular way.