Which do you prefer, adaptive or responsive for a modern mobile website?

Hi _ I would suggest you to go for 'responsive designs' major reason is we have to adopt new technology, all developmets taking place in this market are going as per html5, css3, javascript, and with the invention of new devices we have to do it to make our programmes device friendly....adaptive is ok as long as you are not having command over new things, everyday we get up i see new designs new techniques coming in market so no other option except accepting the changes and developments it's a computer world..................

Responsive for sure as for the main reason it has an approach for using flexible and fluid layouts that adaptable to almost any screen.
If you read the article at MSDN library titled "Responsive Web Design" that states that there are three key features for responsive web design which are; - Media queries and media query listeners - A flexible grid-based layout that uses relative sizing - Flexible images and media, through dynamic resizing or CSS Responsive design should consist all these three features.
If any of them is missing then its not a Responsive design and one fail to apply it for all screens on multiple devices.

Well, both of Responsive and Adaptive have advantages and disadvantages: For Response has advantages in keeping same content, easily achieved with using (css, media queries, and HTML5), and cheaper to use with less time to adapt.
The disadvantages are it’s not giving the user a fully optimized experience, not adaptable to user’s behaviors with mobile especially users not act the same, and websites with large file will need longer time to load with3G connection.
For Adaptive has advantages in speed since The HTML and CSS can be minimal and stripped down, UI and user experience related to user behaviors since you adapt the layout depending on it, and easily to transpose code to create native app that you can submit in apps store saving your team time from learning Objective-C or Java for Andriod.
The disadvantages you will need to create content for each and every device, which also expensive and but yourself on risk or branding consistency and confusing your audience.
So if your website is a corporate website or just a content that will display same information and same structure regardless the device, you can go with Responsive.
As for website with more events and user actions, go with Adaptive.
Sometimes, the best solution is a combination of two types in order to obtain the same user experience objectives far more cost effectively and efficiently than by using any of them alone.

Responsive Design is definitely the way to go when designing websites In response to what Mr.
Alkhateeb said, responsive design does not necessarily imply large files and a lack of optimization, as utilizing lazy loading of images and files and limiting them to relative sizes through either javascript or media queries can easily make sure that the end user only gets the data that he needs Naturally the smaller the display medium used to view the website the simpler the website has to become so not to overburden and confuse the user, which can be controlled via media queries and relative sizing When applying lazy loading and proper organizational techniques with the previously mentioned fact, even the largest of websites will have a rapid loading speeds on any medium and can be limited to accommodate for each mediums processing limitations

Responsive design is the way to go.

In my experience responsive is the best way to go

Responsive

Responsive  is to be good.

responsive because it give quick respons