I bought both the Flash Furniture Mid Back Black Mesh Chair and the SPACE Seating Professional Dark Air Grid Back w/ Black Eco Leather Seat.I needed two chairs for my home office as I often have clients over. At the time of this review, both of these chairs are number one sellers on Amazon in their respective categories. At my previous employment I had an Aeron chair and funny enough I actually like both of these as much if not more. The Aeron had better casters and quality of construction but I always found it kind of mushy, and I had to constantly re tighten the arm rests as they tended become loose from their settings after a couple of hours.Consensus: Pleasantly surprised by both of them and I’m giving them both 5 stars for value and comfort. Note, I’m only in my first week with both.- Ease of assembly – Assembled both chairs within 15 minutes. The SPACE was in particular really easy. Both have the identical number of bolts used in identical places (10 for each chair). The Flash had slightly weaker instructions but overall both were very easy to assemble. I particularly like the touch of the SPACE chair where they warned on the box “don’t use a knife here to open” which could have led to cutting some of the fabric with a large knife.- Comfort – I am 5’ 9” 220 lbs (body builder) and I found both chairs very comfortable. I prefer a firmer cushion and good back support - both were excellent. Same thing on leg height. I had no issues with long terms seating when with past chairs my legs and ass could go numb. I’m currently using the Flash more, but that is because if reading a book or gaming, it’s nice to be able to tilt back. The SPACE has better casters and is better for hardcore grinding away at work if you want a rigid back. I’ve noticed people complaining that the chairs don’t go down far enough. At my height no problem. Especially once I added blocks under my antique oak table lifting it up higher. Perfect ergonomic feel now compared to what I had before.- Quality – The SPACE (made in Taiwan) has better quality construction and materials than the Flash (made in China). Aesthetically I find the SPACE better looking, The Flash has some nasty silver flashing on it, cheaper plastic, and IMHO leaving the nasty dust guards off made it look much better. If I had to bet money on it I think the SPACE will outlast the Flash. The quality of the cushions on the SPACE also seem a bit higher than the Flash.- Value – For the comfort I have now, if these chairs last a couple of years it’s an outstanding value. I seriously considered getting another Aeron and I’m glad I didn’t. I’m part of a start up now and I’m getting 90% of the comfort from the Aeron for literally 1/7th the price from each of these chairs. AND I now have two chairs. Killer value.Overall: Depending on what you want from an office chair they’re both great. The Flash has the advantage of adjust-ability for different seating postures but the SPACE wins when it comes to old school, rigid back grind it out comfort – it just feels a little bit more stable.