yes there is about a $500 difference; so it depends on your price sensitivity; but read up on the differences as I mentioned, and see if it seems worth it to you. One of the differences is the ability to designate Tasks as "inactive" or not. I find that very useful for what-if analysis. In Standard, you can only just completely delete a Task, and then you have to re-enter it. I find that more cumbersome, particularly if with a large complex project.
Scott