I want to clarify some points here. TonidoPlug has default Ubuntu server os (9.04) as its firmware
So one has the freedom to install whatever apps from the ubuntu repository. You dont need to use the Tonido applications if you dont want to. & another important fact to note is that Tonido applications are self contained. You dont need to go through the Tonido servers if you can do portforwarding.
It always pains me when people compare pogoplug and Tonidoplug on same footing. We honestly beleive TonidoPlug is an ideal device for both hackers and casual users. We dont restrict the device in anyway as pogo does. The only difference between sheeva and tonidoplug is that TonidoPlug doesnt have jtag.
Finally, users need to decide what is good for them
Note: I am associated with Tonidoplug
My impression (without actually using them) of the TonidoPlug and PogoPlug is that they are basically locked into the ongoing services offered by those vendors. Probably great for a lot of consumers and I wish them good fortune in the market. While I certainly appreciate something that will work right out of the box, I want the flexibility to customize without purchasing someone else's packaged service or going through a vendor website to access a device on my own network.
The HP thin client looks pretty interesting, but if I were going for a user interface, I would probably be thinking more along the lines of the Acer Aspire or the Asus eeePC.
I did find another plug-type device that fills my immediate needs right out of the box, but does not have much horsepower -- and there is no indication that it can be customized (but it does provide a straightforward method for loading new firmware). The company has a number of other interesting devices as well:http://www.addonics.com/products/nas/NAS2XU2.asp