I like it, mostly because I like overcast.
However, if I may make a recommendation (Please don't hate me, I'm one of those guys who LIKED portfolio reviews during graphic work...)
1) Make a copy of the text layer. (Select the text layer, click the Copy button (the one that looks like two stacked photographs under the layers)
2) Go to the Layer menu, and pick
Layer to Image Size... (This gives room for the effect work)
3) Use the "Select by Color" tool (the one with the little finger pointing at colored boxes) and click outside the words.
4) Go to
Select-> Invert (This selects the text)
5) Choose
Select->Grow..., and choose 3 pixels (3 Pixels usually works, 2 for smaller text, 5 for headlines)
6) Double click the foreground color, and choose White.
7) Select the Bucket Fill tool (It's the Bucket

) and make sure "Fill Whole Selection" is selected in the tool options.
8) Now, drag the original text layer on top of the white block we created and... Tah-Dah! Contrast!
For extra effect, you could Gaussian Blur the White layer (Filters->Gaussian Blur) to make the anti-shadow fuzzy, or maybe just make the white layer a bit transparent (the Opacity slider over the layers) to make the contrast not so tight.
NOTE: Why Select by Color outside the words, then invert, instead of selecting the color of the words? Because I want my original selection to enclose every bit of the words, including antialiasing. Trying to do that by tweaking the tool will work, but it's a pain. Easier to select all the bits outside (transparent), then invert the selection
