Marg, I believe the machines are pretty much equal. I don't know for sure, but I'm pretty sure Respironics has climate control. Also something close to easy breathe technology. I don't think you could go wrong with either machine. I have used both and could not tell any difference (have never had climate control). I see no harm in following the recommendation you got, or get the one you like the best, though a few weeks trial is nothing like using the machine for a year.
Marg, on behalf of The SleepGuide Crew I welcome you to the forum. We're glad to have you. Both ResMed and Phillips Respironics make fine machines. Just be sure you get one that is data capable. What machines are you trialing?