I guess for me when doing legit 10 day backpack hunts, one of the few options is the Spartan. Anything over 8oz and the weight penalty isn't worth it and I'd just as well shoot off my pack like I did before. As with everything when it comes to backpack hunting, the lightweight version is typically not as good as something that is heavier so we have to play the game on where its worth the penalty and where it isn't. I was shooting off my pack just fine, but for 5 oz, the Spartan is worth the small penalty. Some guys agree, some guys would still rather shoot off their pack, and a very few bring a heavier bipod. Most of the sheep hunters I know use them and the ones that don't typically shoot off their packs. I can't find any other bipod that is worth the weight penalty for that application IMO. And when dealing with alders and willow, something that attaches/detaches in literally less than a second is awesome!
With that said, I can absolutely see why people don't like the Spartan. As advertised, it's features are limited to lightweight and a little bit of stabilization - typically paired with resting the butt of the gun on a pack. But again, if you got a 55lb pack, are looking at a 10 mile pack in, and need a bipod; it's the winner by a long shot. If you have a daypack on and are doing a few miles a day and want something kinda light, then ya, there are better options; especially if you don't have to worry about busting brush. I typically use a harris bipod for anything but sheep and goat hunting. I will be doing a hunt in about a month off snowmobiles, I will use my Harris bipod for that.