How to write a standalone program (part 3)?

When I was deciding which library to use for developing my application, I was in doubt between GTK and WinForm. Back then, the WinForm was not so good, so I tried to use the GTK# for both the Win32 and Linux platforms. I had a lot of problems because I had to put a widget in a specific position and I needed to make a lot of experimentation to understand how to layout the GTK widgets. In the next project I did, the WinForm API became more stable, so I decided to use it. Again, I found a lot of problems but the program is now finished. The difference between the two class libraries? Personally, I prefer GTK# because is very powerful and flexible. Unfortunaly, on the Windows platform the look is not so good as on the Linux platform, and the need to include the GTK library for Windows increases the space requirements and the startup time on the CD-ROM media. Using WinForm, the application requires less disk space, but under Linux the interface looks alien.