Looking really good dude, especially the first one. You can tell you're getting a lot better with each new sig.
Fonts can be tricky if you're after something very specific, in the end I always have a 'less is more' approach, and usually stick with small arial. Backgrounds aren't as hard as you would think, next time you're screwing around just put a bunch of brush strokes down on seperate layers, put on a gaussian/motion blur, change the blending to overlay or light screen or basically whatever looks good and then move the different layers around a bit. You'll be surprised how good it can look.