Yes, it bloody is. Take it from someone who's worked professionally with it for over a decade.
I'm glad that you are talking from experience. Most people who shout "MFC sucks" have never used it extensively. I used to be one of those people myself.
I have worked with it professioanlly for six years. I have alwo worked with other toolkits. They all have quirks that make them suck in some way. Often these ways of suckage are the same as in MFC. Perhaps you could elaborate on what aspects of MFC it is that you think makes it suck so much more than other toolkits?
So if you're only targeting windows, why wouldn't you use the infinitely better winforms?
There could be lots of reasons. Perhaps you want write all of your program in one language? It's not like it's an order of magnitude more difficult to use MFC than to use winforms.
Yes, and if you have a legacy code base that uses MFC, that is exactly what you should do. If you're writing new code, use something else and leverage the huge library of code for that.
I am not completely against using MFC for new projects today. It does make certain types of UI a lot easier to create than any other toolkit. Also, unlike what was claimed in this thread, MFC is just as supported as any other library that comes with Visual Studio, and it is still being actively developed. There also exists excellent third-party components (BCGsoft, CodeJock) for it that have been refined for a very long time, and contain some stuff that really doesn't exist for other toolkits.
Of course, it would not be my first choice, but if the situation and type of application is such that using MFC could save a lot of time, I would at least seriously consider it. Shipping on time is a nice feature to have.