There are lots of succesful stories with (even big) businesses using PS 1.7.
In my experience and excuse the lack of modesty but it is not a short/light one the vast majority of apparently unsolvable issues are coming from unsuitable hosting parameters, bad modules, overrides etc meaning particular reasons not general ones.
And I agree to the recommendation that a running medium sized business needs to have a developer close rather than searching the general forums for solution to apply to a circumstantial issue.
Just my 2 cents, I am not looking for work on PS forums quite frankly avoiding it having other sources for it.