I sometimes use tab browsing on a Android Tablet when one site is taking a long time to load, so I open another website to browse while I wait for the other website to finish loading.
I like Opera Mobile 12 Tab Browser since it is pretty fast, and easy to switch tabs between websites, and supports HTML5.
I find my browsing experience is much harder and slower when I try to use multiple tabs on a mobile device. The entire app will usually slow down as it tries to manage multiple tabs. I usually just have one open because of this.
I agree it can be slow browsing the web with multiple tabs on your phone if the sites you are on don't use a mobile theme for mobiles on the websites, or the sites have a lot of flash video, and javascript, Java, animated gifs, and other scripts on it, and your mobile has less then 512MB of RAM, and is slower then 800MHz or 1GHz.
