Yeah, I'd have to agree with Diamond. It's a fantastic start.
Since you've addressed the gray outline, I won't beat a dead horse. I like the colors, very vibrant and alive. The land masses and shapes are cool as well. And yes, the mountains look good. I'm not sure how I feel about the hills though, especially on the eastern isthmus of that large central island; almost too pointy, maybe?
The lower right hand section threw me for a second until I realized it was an incomplete land mass.
Also, I think the font and labels are perfect for this map!
It's a great start and would love to see how this progresses! Have some rep!