I'm not sure what the other HIX presses are like, but we have a HIX HT-400D and love it.
We were torn between using a swing-away or clamshell, but we went with the clamshell in the end. I would imagine clamshells are easier and faster to use, but you do have the problem of heat rising in your face when you're standing in front of it for hours.
Mark has an ancient 15 x 15 swing away, but it's lost its temperature knob and is not a digital. You need to count to yourself when pressing. I'm glad we got a new one.
