Upgrade from 4.0

Hi all!
I'm compiling information to present to my boss about upgrading our old Vista 4.0. I'm a little fearful that knowledgeable support may not be available in the near future. I'm also scared for our data's safety since we backup to tapes on a local server (we have 10 tapes that we rotate through).
I have been with this company since Sep. 2009 and had never used Vista before, so am learning (the Financial end, anyway - we have others who handle purchasing, job control, shipping, inventory, etc)
My BIG question is...
Does anyone have an opinion on Epicor Express web-based product vs. an on-premise upgrade/install of Epicor 9.0??
any info / insight is appreciated :)