You want to scrunch as much detail as possible into h1 and h2, while making them as short as possible. I'd change the blue h1 text to show on one line. Shorten the h2 text and make it more concise.
The overall layout is good, color scheme is easy on the eyes. Make the picture of the application about 75% of current size and sharpen the image. Bold the navigation bar on top, or at least space out the letters a little more.
On the rentr application page the difference between the smaller and larger text is too large. Cut the sizing difference a bit.
Regarding the copy - keep testing. Again, get as concise and detailed as you can.
Good luck!