In answer to your questions:
1. Yes, as of the latest version, Vantage is now full responsive: http://www.appthemes.com/themes/vantage/
2. By default, the theme requires the user to register before they can submit a listing. Any change to this functionality would require customization of the default theme on your part.
3. You can set a listing plan and apply it to all categories, however these are per listing prices for which you set the price and duration, rather than a subscription fee.
4. You can use the "near" search field to input city, state or zipcode
5. Due to the digital nature of our products, no we do not offer trial periods or refunds. Once you have made a purchase there is essentially no way to "return" the product.
6. The initial purchase price includes a lifetime license and 12 months of theme updates and support. You can read more about this on our pricing page: http://www.appthemes.com/pricing/
7. Whilst themes offered by various companies for the same purpose appear to have similarities, "not all themes are created equal". As well as its clean and appealing design, well written and commented code and ease of use, we have a top notch team who continue to develop our themes (giving more of the features you want to see implemented), dedicated support team, and an active community. Vantage itself has some exciting new features to come in the next major release http://www.appthemes.com/releases/
The email for the site you tried must have something to do with how it is set up, as the WordPress name should not appear by default. There are no specific settings for this in Vantage, however there are plugins which will allow you to customize this further. Vantage uses the native WordPress login functionality, so it is compatible with WangGuard plugin, and
WP-reCaptcha if you wish to add these to the registration. Thanks.
