I have that same press, we bought it used from someone that wanted to make things out of their basement and it never worked out. I'd suggest looking on craigslist instead. You can pick up a brand name, solid press for that same price. It might take a couple of weeks before you see it posted, but they come up all the time.
There are issues with it that I'm not crazy about. I have a Infrared temp gage and I check the temp with it all the time. It appears to be fairly consistent, but when I press things, I almost never get to use the times recommended. For example, I had an item recently and the manufacturer said 25 seconds. 25 seconds on that press at the proper temp- horrible. 35 seconds-horrible. 45, horrible, 50- better. Had to end up at 80 seconds to make it work. I can't seem to use any factory recommendations, it's all trial and error,which gets expensive.
However, people with the high end presses seem to be able to use all the factory recommended settings. So what's the time and frustration all worth?
I'd take a used, quality, swing press over a new clamshell any day.
The clamshell design can also cause many issues. If it's anything thicker, it doesn't hit flat, so you'll have uneven pressure, which will ruin the graphic.
Also, the gages are in celsius, so figure on having to convert everything you do to that.
I'm not doing t-shirts, so my advice might not apply, but get a good used one instead.