For various reasons I have been looking into kayak ergometers for a while, including being able to train when I am at home babysitting
Anyway, I found this website of a Dutch marathon paddler/dealer for Dansprint and Speedstroke ergometers) who incidentally was about to have a demo day just around the corner (this was last year, November 2008). After a few test and taking part in the Open Dutch nationals 200 meter indoor sprint (in which I, a mere humble Master, did beat the Belgian Senior marathon National Champion by a few seconds. Ha!

)
So my decision was mad then, a Speedstroke it should be. Now this was a bit of a problem because it was about twice as expensive as the much cheaper budget model (manufactured and sold by the same guy) I was actually looking at buying.
To make a long intro short: this week I finally got my Speedstroke and after assembling it I was thrilled! It does feel like "real" paddling, the motions are fairly fluid and you can paddle with a variety of techniques (fi. straight along the boat like with a regular paddle, wide like a wing paddle etc.).
Assembling was pretty straight forward, if you have assembled a few pieces of Ikea furniture you can do it. Connecting the ropes/shock cord took some attention but in the end it is easy as pie. So far I have not used the PC software yet. My Speedstroke is in my garage (the only place I can store it without little kids' fingers prying all over it

) and my PC is not. Besides I use Ubuntu Linux and I don't think the software is made for that OS.
At first, start paddling on a relatively low speed, say 10 km/h, without much resistance from the wheel. Focus on putting in your "blade" up front and on using proper technique. You won't flip so any rough/uncontrolled strokes are not punished but beware of trying to paddle too fast too soon. Make sure what you do is right. If you do not use a proper technique on an ergometer you may actually acquire bad habits for real boating.
As I paddle a sprint K1 I like to sit high and the Speedstroke was just a little bit too low for me. So I put a piece of wood underneath the leg you sit on and my angle changed into a much more comfy position.
That's it for now, as soon as I have more experience with the Speedstroke I'll be back! this could be soon enough though as I paddle it almost on a daily basis