Individual fit makes a big difference here. I prefer a Steelcase Leap or (especially) a Haworth Zody to an Aeron, and I know others who prefer Aerons. Based on my experience, those issues w/ your Leap are unusual.

I also really like using a lap desk and coding in an Eames lounge chair, but that's probably not as good from an ergonomic standpoint.

(Incidentally, I live within an hour's drive of where all four are produced, and great furniture is occasionally quite cheap on craigslist here. My wife snagged an Aeron for $50!)