Like SKT, I'm in the best shape I've ever been. My resting heart rate is in the 40s. Unless I've kicked-in the afterburners, in-ride I average 146 when cooking along. I can ride anywhere, and any distance I point my wheel. 18% grade? No problem. Miles and miles at 7%? We can do it. A nice 45-miler before work? Do I have to stop and go to work? 20 MPH headwinds? I don't like 'em, but I can ride 'em--uphill if need be too.
I find all of this absolutely amazing. 27 months ago I couldn't climb the stairs to my apartment without huffing and puffing. My first bike ride was 2/3 of a mile--and I had to stop and rest half way. Then I needed a nap afterwards.
What I find even more amazing is that from what I've learned, if I keep at it, I'll continue to improve for another 2-3 years before plateauing. Yikes!