I do way prefer the Aeron over the Mira. The back support on the Mira is better but... Once I've used the Aeron's pellicle mesh (both in the back and on the part you sit on), I simply cannot go back to a chair which doesn't have a pellicle mesh.
The Aeron is a bit cheaper and you can find quite some at a bargain price if you're in the U.S.
I forked that and $300 or so on a Topre-switch based keyboard (an HHKB Pro 2 but YMMV, some people prefer bigger keyboards -- I'd rather move my hands / fingers as few as possible). Probably that a real split / symmetric keyboard like the Kinesis Advantage or the Maltron are even better (they're using Cherry Mx switches, no Topre).
The Aeron is a bit cheaper and you can find quite some at a bargain price if you're in the U.S.
I forked that and $300 or so on a Topre-switch based keyboard (an HHKB Pro 2 but YMMV, some people prefer bigger keyboards -- I'd rather move my hands / fingers as few as possible). Probably that a real split / symmetric keyboard like the Kinesis Advantage or the Maltron are even better (they're using Cherry Mx switches, no Topre).