Blocking it doesn't make quite as much a difference as it does with pure wool, but for me it makes enough of a difference to make it worth the effort.
I run my Plymouth Encore projects through the washing machine on cold/gentle cycle without detergent, pin it out, and then when it's almost dry I steam iron it. I actually touch the iron to the yarn lightly and briefly without any pressing cloth and it's worked for me every time--no melted plastic on my iron and the project still looks and feels great. I just did this to a blanket I made from Plymouth Encore for a friend's baby (Stacey Trock's Pastel Petals Afghan) and it made a significant, positive difference with the stitch definition and edgings.