If you're happy to pull the iMac a little closer to you, you'll find using the scaled setting great, and you won't miss the 27" as much.
I may, on occasion, need to zoom-in to read text more comfortably, but this is trivial on my Trackpad; not sure this experience carries over with the Magic Mouse since I've never had one.
Thank you for this tip!
I'm just really pleased with this purchase. I had my 27" iMac mid-2011, I believe, for too long and was way overdue for an upgrade. I was going to hold out for the highly rumored 27" iMac released this year, but the color options and nostalgia factor sold me on this model.