I have tried various popovers earlier and I am really unsure if I should install a new one. I know that they will get me leads, it has done so in the past, but I find them kind of annoying.
When I visit a site with a popover, it´s ok to see it the first time you visit the site, but if it pops up every time you visit the site, I would probably not visit the site anymore.
If I am going to start use it again, I might use one of the following:
I found a free popover script at hotscripts.
If I am going to buy one, there´s always Instant popover