Artio does not like/irreparably alters my website when I uninstall. If you are wanting to try this program beware that you may not be able to remove it. (NB. This may just be I am doing something wrong. however when I uninstalled I got nothing but 404 errors...)
2nd Whilst I completely agree that if you like something you should pay for it. The link hopefully advertises to potential new software buyers. Is it possible that the advert be less intrusive??? Perhaps at the footer? Most people are commenting that it appears to be 'plastered' and having used it there is only one link on every page though this is a very visible link that may intrude on a website.
Very good module. And definitely worth paying for which would alleviate all of the negative concerns so far commented on.