All the films are listed on Mill Creek's website. The suggested price on their website is $15, so this is a pretty decent deal.
Mean Guns is a mix of fairly recent Westerns with a few old PD films tossed in. The website reveals a few films that aren't available in the other Western sets (except the 250 movie boxed set.)
The Family Pack looks like a pretty decent collection of old family films. If many of them are those we've seen time and time again (Gulliver's Travels, The Inspector General, The Little Princess), they're still good for the more general audience, and some of these are, according to Mill Creek's website, aren't on any other collection, including Father's Little Dividend (which looks like a fairly high-budget movie) and The Magic Sword (from Bert I. Gordon=not so high budget).
I've grabbed my copy of Alfred Hitchcock's films. It doesn't look like Mill Creek has taken much advantage of Hitchcock before, but I've seen Thirty-Nine Steps and a few of the others several places. I haven't seen the silents elsewhere, though--though I have a hard time imagining how these British movies are legitimately in the public domain.
The John Wayne 20 pack copies a lot from the other Mill Creek packs, but it's a cheap copy of McClintock and Angel and the Badman, plus a bunch of lousy B&W Westerns from the 30s.
They're missing quite a few I'd like; in particular, I'll have to get Cult Classics from Amazon sometime. Do other stores have a different or broader collection?