I love my elliptical but don't use it all the time. I've been on ellipticals (usually cheap ones) that really feel funny. I believe it is the stride. When I was looking for guides on buying ellipticals, they advised never to buy an elliptical with less than an 18" stride. My elliptical is adjustable and goes from 18" to 24".
Also, there is a learning curve with ellipticals. When I first started, I could only do a few minutes. Within a few weeks, I reached the "forever" point which is when you can go on forever, 20, 40, 60 minutes, it doesn't matter.
Overall, they are great machines and supposedly the best thing to do if you have bad knees or knee issues.

). I never use it and go to the gym for the Life Fitness.