ResMed Airstart 10 vs. Airsense 10 vs. Airsense 10 Elite?

I'm looking to get my first CPAP machine, and since my insurance isn't helping me at all, my best solution is to purchase one online. Everyone I have spoken to recommended ResMed, so I narrowed it down to these 3. On cpap.com, the price goes from $249 to $598 to $699 respectively. Can someone help me choose which one would be best? Thanks so much.