I have this pin press:
It presses one inch buttons, and is totally easey to use. However, it cost considerably more than the ones you were looking at. What are you planning on using the machine for (making buttons, obviously) -personal use (just making buttons for yourself and your friends) or mass production (making large numbers of buttons to sell)?
Also, with stuff like this, you totally get what you pay for. A pin press that costs $15 dollars and is plastic is not going to last nearly as long as a metal one that cost over $100 (at least I hope, 'cause otherwise I got JIPPED
). Ease of use and availability of parts is also an issue. I have never had my press jam, and I can order parts for 1000 buttons for $40, including tax and shipping.
Do any of those machines come with a circle cutter? You will need one of those too, depending on how many buttons you plan to make (unless you want to cut out all those circles by hand... my blood-pessure rises just thinking about it!).
I would say that those machines would be better than one of the handheld presses (oh man... those things and I do NOT get along). So... you are just going to have to figure out how much you want to spend, and go from there.
Hope this was even remotely helpfull.
Oh, P.S. -- My press,with circle cutter and 1000 parts was a little over $200. I got it in August, and since have sold the entire thousand, and ordered another batch of materials. I have recouped my costs, and get a fair amount of bussiness (I sell them mostly to bands and local venues). So the more expensive one can pay off, depending on the intended use.