An Elliptigo requires a rather significant investment, and the next best thing to actually trying one out is to read some unbiased reviews by owners of the machines. I think I posted a pretty objective and semi-detailed report here, but I barely scratched the surface compared to what this guy is doing.
When I first visited ElliptiGo Galveston, it took me a while to figure out that the writer wasn't really a dealer. It's one of the most thorough product review websites I've ever seen. I can also relate to his experiences regarding the [literal] pains of traditional bicycling for men of - how shall we put it? - a certain age.
So, if you're undecided, or just seeking some additional input or resources about the bikes, I highly recommend spending some time on the site.