I too find this highly annoying. It does not fit in with the rest of the WordPress theme, and I think that if everyone did this then the blog admin is going to start looking like a visually terrifying web page from the late 90's-early 2000's.
Additionally, the WordPress plugin guidelines (http://wordpress.org/extend/plugins/about/guidelines/) specifically state:
Plugins should not hijack the blog admin. It is fine to include an Upgrade prompt on the plugin admin page, but not throughout the blog. It is acceptable to embed a widget on the dashboard but this should be the same size as others and be dismissable. It's fine to put an error message at the top of the admin for special cases, but it should be linked to a way to fix the error and it should be infrequent. Any form of "nagging" is absolutely prohibited.
In general, things like banner or text link advertising should not be anywhere in a plugin, including on its settings screen. Advertising on settings screens is generally ineffective anyway, as ideally users rarely visit these screens, and the advertising is low quality because the advertising systems cannot see the page content to determine good ads. So they're best just left off entirely. Putting links back to your own site or to your social-network of choice is fine. If the plugin does include advertising from a third party service, then it must default to completely disabled, in order to prevent tracking information from being collected from the user without their consent. This is the method commonly known as "opt-in".
Your plugin does both of these. (and this could be easily seen as advertising within WordPress). Although, the second one (advertising) I'm not too worried about, as a developer I know that its nice to at least receive some compensation for something you've put many hours into (as you obviously have) -- so I can't fault you for that. The plugins page however, looks terrible, is intrusive, and is against WP plugin guidelines.
Aside from that, it's a really good and handy plugin, but I absolutely hate anything that touches my WordPress admin outside of a single settings page. At best, this should be "opt-in".
I would say that if this is not fixed by the next version I'll likely downvote the plugin.