What is the best 3D Field solver tools

From my many years of experience, here is a very short summary (I can elaborate if necessary):

For closed systems such as waveguide filters, diplexers, etc, both HFSS and CST are useable ? personal preference dictates the choice. My preference is HFSS simply because I have used it longer than other software.

For radiation devices, such as horns or reflector antennas, only CST works. HFSS either does not work (memory size limitation), or the results are highly inaccurate.

Hi
many tools,such as XFDTD/OptiFDTD/EastFDTD/CST------

Interesting discussions, while some are right on, others are totally wrong.
I do not know cheng or yuyu personally. Every post by cheng is so wrong, while every post by yuyu is right on.

The above post by "maxjames" is so wrong. The fact is that we have seen many new features implemented in HFSS, CST MWStudio and other 3D solvers over the past few years. There are many new commercial products since cheng or yugy offered their opinions. It is becoming more and more difficult to choose a single "best" 3D field solver. It would be foolish to believe any simple answer given by so-called expert. Newbie should describe their problem in details when looking for advice.