We've used TRichView just recently to do HTML email functionality and found it quite adequate. We did evaluate WpTools and it does do exactly what we wanted however for our needs it was just too expensive especially when we always try and purchase site licences.
One thing we did find with WpTools is that it did implement a visual component or set of visual components that you could drop onto a form that implement the whole WYSIWYG UI (e.g. toolbars and such). It took a bit longer with TRichView to achieve the same thing.
Regarding conversion from/to html - TRichView can export html natively, however requires third-party libraries to import html which unfortunately (for us) are not commercially backed (i.e. community driven). So we've resorted to storing all content in RichText natively and only when sending the email do we convert it to html. WpTools has the ability to import/export to html natively.
