This is a fairly basic diary - it offers no integration with other calendar programs, but if you want somewhere to easy record your thoughts on a daily basis, this works quite well. On the left it is a category bar, where you can add categories, and a little infotmation to each. This is isn't linked to diary posts, rather it's another way of recording info for a particular day. The left hand bar features the calendar, and a large window for either searching your entries, or displaying a word cloud of most often used words or tags.
The best feature of Work Assitant is its autosaving - you certainly won't accidentally lose things, as it's all saved as you go along. The main text window allows text to be formatted in bold, italic or underlined, but there are no options to change the size, font or color.
For personal use, ReNotebook is a reasonable free program, and with its export and backup features is quite secure. It's not really suitable for professional usage, as it is too basic, and is restricted to text only.