Every company is different, every project is different and every client is different.
I think it's just as easy to fail by following scrum (or any other methodology) too closely in an environment that doesn't fit the methodology as it is to fail because you follow scrum too loosely in a project that does fit.
At the end some generic answer in a QA site is no replacement to serious analysis of your own project, company, team and clients - there is no magic formula and you have to make your own decision.
