I am new to Klok and still using the Lite version. First and foremost, Klok is a fantastic and appealing software.
I was using it when I noticed that Klok does not support attachments at time entries level; which I thought would be a great idea. (It beats pasting long paragraph of text into the comments box). Just a thought.
Nevertheless, I will continue to use Klok and will upgrade to the Pro version when the need arises.