I bought a couple of the new Middleman Jacks as gifts because I knew they'd probably be broken or lost. (One is currently missing in a pre-teens room)
They actually haven't been too bad. The fit and finish isn't up to speed with Case. But they're a lot cheaper.
I do agree with those that say if you can find an older one, go for it. The new ones aren't terrible. I've noticed the fit and finish on the Rough Riders seems to be better for the most part and they're around the same price.
I have a friend I gave one to as a beater and he's really happy with his Middleman Jack. He's used the crap out of it. It's developed a little bit of blade wiggle but he said that was after he did some digging with it. Not something I'd do with a pocket knife.
Are they great? Eh, not really. They're okay. I like the Rough Riders better. They just don't make a medium sized jack and that's what I was looking for.