I am just wondering what are the benefits of using open-source-router or RB532 with Kamikaze
while you can buy off-the-shelf router for cheaper price ? What this combo does differently ?

thanks,

You should ask yourself this before using openwrt.

If you have Linux know-how: because you can do anything you want with it. (for example I'm running a custom traffic shaping setup that no off-the-shelf router offers)

If you don't have Linux know-how: uh, well, because it's stable? Anything that runs Linux, cannot be used to its full potential by someone who doesn't know Linux, though.

Currently, I am using this combo (openwrt & rb532) for the project I am working on, basically R&D, implementing a TDD system
on top of 80211g protocol for longer range. For this task, I used Madwifi, openhal and did significant code modification.

Beside R&D type of tasks, I wondered where others using openwrt with routers.
Traffic shaping you can do with $55 3com router too, check this router CRWE454G75....

Then waht else......someone help me ......plse...

While there are some off the shelf routers that support traffic shaping, it is usually not possible to design your own custom shaping setup. In Linux you can choose from several different schedulers and behaviours (hsfc, htb, sfq, prio, red, ...) and combine them in any way you want. I'm using a HTB (one class per user) -> PRIO (prioritization depending on type of bandwidth) -> SFQ (balance concurrent connections) approach to ensure fair bandwidth sharing and quality of service. Off the shelf routers do it differently i.e. not the way I want. With off the shelf routers you're stuck with whatever feature set and flavor they offer; with Linux you can create your own flavor. Also, a router you can put OpenWRT on, is not more expensive than the 3com you mentioned... that 3com you mentioned is actually more expensive than a WRT54GL here.

I guess most people here install openwrt on off-the-shelf-routers
Take a look at the supported devices, many consumer-routers  are supported.

and also take a look at the package-directory an you will get an impression what you can do with openwrt http://downloads.openwrt.org/kamikaze/packages/mips/
and if you need something else you can compile it yourself so I guess you can do almost everything.

so tell me which 50$ router with stock-firmware has this options?

and I guess many people like openwrt because it´s modular, you only need to install the packages you want, so you get a slim system if you don´t need special functions, and you don´t waste (flash-)space for things you don´t need (and have more space left for the things you want to use). 

For example I run a openvpn-server on a "cheap router". If you want a vpn-server out of the box you have to spend 200 euros and more.
Another router has an usb-harddrive attached and run a nfs-server on it.

and I guess the advantage of board-based routers over consumer-routers is, that this hardware is modular, too. You can decide which wifi-card you want to use, antennas, maybe the amount of ram, or whatever.