I use a very old, steel, Summit Cobra Climber that's open in the front. It weighs about 27# total and I've had it for several years. I bought it from a buddy of mine that upgraded to an aluminum Summit and he loves it. Actually, all of my hunting buds use Summits.
The best thing I did with mine was to buy a net seat to replace the bulky, fold-out, 3 piece cushion one. I also added Summit's foot stirrups and the adjustable shoulder straps they sell as well.
Yeah, it's kinda heavy but it sure is comfortable, quiet, and it's very solid when sitting and/or standing.