Clouded, this boy's future is.
You really need to use your own judgement. Who will want to take responsibility for leading or misleading you in such a shaky matter?
There are problems in both libraries. The problem with Forms is that they are based on the very obsolete and rusty Windows API and inherited a number of Windows problems. WPF is actually a brave step to get away from Windows. WPF has very little to do with Windows API as it is based on ActiveX, and only the main window obey some Windows API rules, while all inner elements don't use anything from Windows and don't use Windows message pumping. Did your hear about non-Windows Microsoft OS called "Singularity"? It is based on CLR build directly on top of the HAL, without the unmanaged layer. It works, and development of the possible Windows replacement based on Singularity technology (code name "Midory") was announced. There are other "pure-managed" OS projects, please see below. In principle, it would be a great boost for non-Windows APIs like WPF. However, we don't know any further plans. We know that many good project have been undertaken, and a lot of complete trash was successful on the market.
Please see:
Microsoft Singularity:
http://en.wikipedia.org/wiki/Singularity_%28operating_system%29[^],
http://research.microsoft.com/en-us/projects/singularity/[^];
Cosmos:
http://en.wikipedia.org/wiki/Cosmos_%28operating_system%29[^],
http://cosmos.codeplex.com/[^];
SharpOS:
http://en.wikipedia.org/wiki/SharpOS_%28operating_system%29[^],
http://www.sharpos.org/[^];
ETH Zurich — Microsoft Research Barrelfish:
http://en.wikipedia.org/wiki/Barrelfish[^],
http://www.barrelfish.org/[^].
Microsoft Midori (code name):
http://en.wikipedia.org/wiki/Midori_%28operating_system%29[^].So, think by yourself. Nobody will guarantee anything.
[EDIT]
Practical advice? Sure. Learn both. And learn a lot more. You need wider look.
Afraid to waste of time? If you are going to be afraid of waste of time, it will lead to even greater waste of time. To minimize such waste of time, focus on fundamentals and also the aspects of technology and detail needed for your immediate work.
—SA