Mars notebook is a neat and tidy application for taking RTF notes. It offers standard features that you would expect for a product like this such as:
An easy to use colourful interface to take advantage of the rich text pages.
Spell checker.
File attachments.
And numerous other features.

However there are also a number of negative points.
By default the English dictionary used for spellings seems to be limited to American English. Admittedly this may be something I missed, as I did not use the program for long.
If you don't run (or remember to run) the application in administrator mode, you get an error about a corrupt database.
The limited version really limits the amount of notes you can take. Not the best way to trial the software.
The ability to encrypt is also disabled and so you can not test this feature before purchase.

From the limited version I tried, I did quite like the product, and did intend to purchase it. However on further investigation changed my mind.

The main reason for this is I found that this program is provided free of charge to Russian individuals (or at least ones able to read Russian). While I fully accept this is the authors choice, I find a £16 (advertised price does not include VAT which is also annoying) price tag quite steep, especially when a whole section of people get the product for free. And to be honest I also find it quite insulting and offensive. This fact is also presented in a bit of an underhanded way, the information is not on the English website, and only viewable on the Russian website. If someone is so prejudice against someone, solely based on their native language, then it is a little hard for me to justify providing them custom.

I can only rate this 1 star due to the number of limitations.

Nice interface.
Portable.

Trial is too limited to try properly.
Software needs administrative mode to run correctly.
Price excludes tax.
Software is free in Russian language. Authors choice I guess, but feels a bit racist.