I believe the Cameo has a larger work space (20" vs. 15" width). Check overstock.com. My husband got an amazing deal on mine for Christmas ($219 vs. $299).
I would order tshirt vinyl to get you started. Www.expressionsvinyl.com
is great to work with and lots of great tips on how to cut their product.
My best advice, order an additional blade and mat. I use mind a lot and I believe I am about in need of investing in both. I have been using mine for about 2 months now.
I cannot give you a review on the Portrait, perhaps someone else can.