Horrendously intrusive Rated 1 out of 5 stars
I tried this add-on because I thought it would work in the discreet and helpful way that Invisible Hand does, and simply give some additional price comparisons. In the event its assault of grossly intrusive pop-ups when I visited a site such as Amazon made it a no-brainer to kick out at once.
Also, I noted that all the prices that it offered were in $, which was stupid for a user in the UK and visiting UK shopping sites. So, useless anyway, and an intolerable aggravation into the bargain. I note too that one FF add-on developer has very 'kindly' insinuated Window Shopper into the computers of users of his add-on IE Tab Plus, causing a well justified outcry from his user base.