Great plugin

To be a great plugin, it needs to add value to your site, save time but most importantly, work. This plugin does all of these and then some. Taking your site offline when performing longer periods of updates’ can have a major impact on your SEO rankings if not done properly. Using a tool like this helps you take your site offline correctly. Not only important to search engines, most importantly it informs your site visitors/members of what is happening (and why).
I can’t comment on the level of support because I’ve never needed it. That must be a measure of the quality of the plugin, it does what is says on the tin.