EV-DO on Sprint's Unlimited Vision Pack?

[tstack77]

I upgraded to the Touch but have never been able to use EV-DO with the Vision Pack from my old phone/plan ($10/month). The EV icon is always displayed but when I try to connect to the web it changes to 1X. Do I need a data plan or do I simply need to pay $5 more to get Power Vision? Also, what benefit would it be to select the $20 unlimited Power Vision plan? (I apologize for these rather simple questions but the website isn't very informative)