I typically don't like machines at all - I am FAR too A.D.D. to stand the boredom. I usually stick to group exercise classes. But when that's not possible, the eliptical is the only thing I can tolerate for long periods of time because it is fun. You can mix up the speed and incline. I challenge myself to do it without holding on, in order to engage the core a little bit, but that doesn't last long til I'm falling off! I read that doing intervals is the best way to get results and build stamina fast. I'll do 2 minutes at level 5, one minute at level 9, etc. and after 30 min I am done.
More than anything, IF the calorie counter on the machines is accurate, they burn calories like crazy! So good luck and have fun.