I've got a Mirra at work and I'm not overly fond of it. I'm just a sucker for simple leather office chairs.
Specific complaints with the Mirra include:
- Rubber on arms is too "grabby". If you have hairy arms like me you'll find that it tends to pull your fur.
- The handle on the right that adjusts the tilt sticks out too far and is positioned too low. I tend to put my feet under my chair and I get caught up on this.
- The edging around the seat cushion is very rigid. If you tend to lean one way or another or position your thighs in a way other than "perfect form" this edging is uncomfortable.
- I can feel the seat cushion bottom out under my thighs. I'm not a large person mind you - 6' and 165 pounds.
- Plastic seat back can be uncomfortable depending on seating position.
I'm picky though. I fidget a lot while I work. I'd never buy the chair with my own money and would much rather have a traditional leather office chair for 1/4 the price.