I have been using my 3DS for light web browsing the past couple weeks, and I found it surprisingly useful. Although my expectations were somewhat low, due to poor performance of the original DS browser.
Technically, hardware-wise the 3DS is a lot more powerful than the DS; software-wise the 3DS uses webkit-based Netfront NX browser, compared to the DS's Opera browser.
The 3DS handheld clamshell form factor is very portable, truely letting you use it anywhere you want; using it around the house, i.e. on the couch, is no problem at all. Closing and opening the lid puts it in and out of sleep mode instantly. And unlike older devices, the WiFi connection re-establishes quickly and seamlessly.
The 3DS battery life varies greatly depending on the game or app being used. So I have a 3rd party extended battery installed for those power hungry games. Although I have not used the browser in any really lengthy sessions, I estimate that the ext batt can easily last all day
(8+ hrs
) if you're just using the browser, accessing WiFi intermittenly.
The Netfront NX browser as mentioned is WebKit based, same as many browsers like Chrome, iPhone, and Android. So rendering is mostly accurate, but still some very complex JScripts do give you problems. Interestingly it does not load mobile version websites, giving you the standard version every time. Each column autofits to the width of the lower screen, regardless of zoom level, so you can always read texts in a column without horizontal scrolling.
There is no Flash support. However according ACCESS's website, Flash 10 is planned for Netfront NX. I hope it happens eventually and Nintendo decides to supprt it.
http://www.access-company.com/products/internet_appliances/netfrontbrowsernx.html
The resolutions are 400x240 and 320x240 for the top and bottom screens. Only the bottom screen is touch, so you scroll with the bottom screen. I find it very natural to focus on reading the top screen while touching the bottom screen
(yes the classic DS joke that's NSFW...
). Although you do have to click links while they are on the bottom screen, you do learn this navigation limitation rather quickly.
While the bottom touch screen is already small, the on-screen keyboard is disappointingly even smaller. Keys are minuscule, so the telescoping stylus is a must for entering URLs, and I wouldn't type any lengthy texts on it. There is no tabs or windows so you can only load one webpage at any one time.
Despite the limitations, the 3DS browser remains surprisingly good for light web browsing, with its acceptable performance, good endurance, and convenience. I wish the browser gets updated, although I doubt it. On the other hand I'm very interested to see how the PS Vita will perform as a MID.