I have used the Technologic ARM9 based TS-7260 and Soekris Geode (x86) based Net-4801 SBCs. Here is my view of how the new Atmel ATNGW 100 SBC compares with them. Note that I don't think any one of these products is better or worse than the others. They are really directed at different markets and purposes.

In general, the ATNGW 100 trades off expansion for a lower price point. The TS-7260 is PC104. The Net-4801 has 3 volt PCI and mini-PCI. These are the most obvious differences and probably account for why the Atmel product is so inexpensive to a great extent.

The TS-7260 is quite similar to the ATNGW 100 in some ways. Both boot off onboard flash and have SD/MMC slots. Both use non-x86 processors. Both have vendor supported distributions and toolchains. Note that the Technologic product supports a 2.4 Linux kernel while the Atmel is based on 2.6. That can make a difference when it comes to device drivers. Though...if you are not x86, it is more likely that more work is required to get everything working. And as non-x86, the ARM9 based TS-7260 is very power efficient. I would guess that the ATNGW 100 is also low-power (around one watt).

The Soekris Net-4801 is really intended for the embedded router market. It is x86 with both PCI, mini-PCI and three NICs. Power requirements anywhere from 5 to 15 watts, depending on what is plugged into it. It can boot directly off of compact flash and has an IDE drive header. One major difference is that the vendor does not support a distribution or toolchain. But I've found uClibC/buildroot is pretty easy with the Net-4801 as the mass storage uses IDE (either a hard drive or compact flash).

On that note, remember that SD device drivers are restricted to closed source by licensing. So there's somewhat less flexibility compared with compact flash which looks like an IDE drive. However, SD is more convenient than CF in a mechanical sense - it is easier to insert, remove, and handle. I like SD in all ways except for the legally mandated lack of an open source driver.

I'm not certain of the details but I believe there is now a GPL'd SD device driver for linux. My understanding was that it was developed using reverse-engineering and leaked documentation. Once it was added to the Linux kernel, the SD Association finally relented somewhat on their closed, proprietary stance and actually released the SD specs, allowing further improvements to the open source driver. I think this all happened somewhere around the time of the 2.6.18 kernel. But I couldn't find a handy reference so I may be confused about the events or hardware involved. If someone else has a link to the details on SD status, let us know.