Congrats on getting second place! I think your design is great.
I have a Studio and wouldn't go without it. I thought about the GO since it is cheaper and so are its dies, but decided on the Studio because I can order custom dies and use some other companies dies too (there is great information on Quilt Possible's website).
As for what dies to get, I think it totally depends on what type of quilter you are. I love my hexagon die, my apple core, my strip cutters and a circle I use to make faux cathedral quilts. And I'm super excited about my butterfies and alphabet dies that should be here in a week or two. However, I don't think my Mom would use half the dies I have. So take your time and decide what you will use the most. Also, their sales are constantly changing and they have a different daily deal Monday through Friday, so you may want to keep your eye on that too.