The Meyerco is definitely the budget version of the Gun Hammer. It's got AUS8 steel instead of S35VN or M390 like the HTM version.
The biggest difference is really going to be the quality of the fit and finish and quality overall, for that matter. If you look over the reviews, most of them agree that the machining isn't the best. However, if you want to try out the design before you shell out for a full-on HTM, it's a good buy. It's not as good of a knife as the HTM, and if you were hoping that you'd be able to get a gunny at a fraction of the price, you've got another think coming. But AUS8 isn't horrible, and while Meyerco isn't exactly the best production company ever, they're also not particularly awful either.
Personally, I went for the real deal and never looked back.
-edit- Also, if you can get an HTM and a Maxx-Q for the same price, either the HTM is a STEAL, or the Maxx-Q is hideously overpriced. They should be around 40 bucks or so, while the HTM will be around 200-300. I've seen them as low as 170 or so, but if you're paying that for a Maxx-Q, you're in trouble.