which makes sense for them... Lets assume they went with your solution. All fine. up and running in no time. Then you get hit by a bus or leave the company. Then things go wrong. How are you going to explain this to senior management.
If they take IBM/Oracle/etc. and things go wrong? you call them. they fly over an exec you can beat up and all is fine.
If they take IBM/Oracle/etc. and things go wrong? you call them. they fly over an exec you can beat up and all is fine.