I just bought an Asus WL-520gU
which is very similar to the one you're looking at. Same processor, but half as much ram and flash memory and only 1 usb port. I'm a cheap bastard and they have been on sale this month for $20 bucks after rebate.
Basically there's a whole bunch of routers that run similar software, namely linux (and many of the most popular use similar chips from the same manufacturer, namely broadcom)
Since linux is open source, communities have sprung up to modify, update and push the envelope on the linux that runs on these things. This has resulted in these community firmwares being better and more up to date than the ones produced by the companies, and also add crazy features like full PBXs, authentication for sharing like a cybercafe, solid virtual private networking, etc. A real success story for open source, linux, and community projects.
There's a few out there:
is probably most popular.
is also very popular and this is the one I'm using.
is more of a technical build.
And people also have good things to say about Oleg
, but it's also on the technical side.
They can do anything that linux can do, subject to the memory and processor speed on these little things, but since that isn't much they stick to the things that people want from routers, i.e. share an internet connection, share a printer, share files, work well with VOIP, bittorrent, gaming, share your connection with strangers subject to limits of bandwidth and authentication, and have the latest security.
DD-WRT has a standard build, a build with Open-VPN if you're connecting from outside and want full encryption, and a VOIP build if you're using internet telephony. The wikipedia articles on the firmwares give good details, e.g. http://en.wikipedia.org/wiki/Dd-wrt
They need separate builds because they're made to fit into the 4meg of flash memory on common routers, so they don't just put everything in one build. That WL-500g Premium v2 looks like it has 8meg flash so you could install the DD-WRT mega build.
Why update? People have experienced increased stability, easier to use web UIs, more features, and better support from the large enthusiast community.
Asus is pretty popular for their hardware. Their firmwares (which are just their version of linux) tend to be roundly criticized. The old Linksys WRT54G version 1 through 4 were very popular, but the new v5+ ones have 2 meg of memory and different software, so not as flash friendly (tho I see that DD-WRT now has a 2 meg micro firmware they've shoehorned in). After Linksys went to 2 meg on the v5 to cut costs, they released the WRT54GL
(L for Linux!) to serve the folks who still wanted to flash with 4meg firmwares, so that model is still popular.
The DD-WRT Supported Hardware
page will give you an idea of how routers compare with respect to their processor speed and make, how much flash memory and RAM they have, how many lan ports, if they have USB ports for file storage and print serving, and their current state of support with DD-WRT. Tomato sticks to a smaller subset of those with Broadcom chips: Tomato - What will it run on?
Tomato doesn't claim to support USB ports officially, but a blog post has a 3 min howto that is supposed to get it working. I'll post if it works when my USB to parallel cable arrives for my crappy old laser. If not, I'll be moving to Oleg or DD-WRT for USB printer sharing.
As for the actual process of flashing, it was very simple on the Asus. Holding the reset button for 30 seconds while plugging in the power put the router into a firmware recovery mode. Then I ran Asus's little firmware recovery program for Windows and browsed for the Tomato firmware and pressed update. Took 2 min. Flashing back would be the same. Some routers aren't as friendly, but there's alot of walkthrus around.
I like Tomato much more than the stock Asus. My Asus came with their version 2 firmware and I flashed to the v3 from their support site before trying Tomato. Tomato is basic columns of black text on white, without Asus's broken graphics trying to make it look like you're working with a molded plastic toy. The Asus is riddled with spelling and translation errors. Tomato has more detailed options and pretty ajax real time bandwidth graphs. It is designed very logically and minimal.
I'm not doing anything too fancy with mine, but the one thing I really wanted from a new router was decent QoS. I want the router to give priority to VOIP calls at the top, web page requests next, game traffic next, then things like large file transfers and bittorrent at the bottom. The Tomato setup for QoS is MUCH better than the Asus. I wanted this feature to be powerful and configurable, and I was not going to be satisfied with the Asus firmware.
Get the Asus, or the Linksys GL or the Buffalo ones that are all Broadcom and you'll be happy. If you live in a concrete bunker, get one with more antennas, and a better power converter for higher signal strength. If you want to be a bittorrent super node, get one with a beefier chip that can handle a jillion connections. I just went cheap.
Is there any reason you liked the Asus specifically? Is there anything specific or fancy you want to do with it?