I had one of those liquid metal ones lying around. It's older, but not sure of the model. I don't think it matters much which kind you get.
Couple of suggestions though from my experience:
1) make sure you have something that will cut the foam board cleanly. I did not. I ended up using a knife and it left it not clean at all. When the sides fit together there were gaps in places. I ended up caulking all the gaps, but I'm sure it would hold the cold in better if the edges were cleaner.
2) be careful of soda bottles as the ice jugs. I've already had 2 bust on me.
Mine works pretty well, though...I don't do lagers, but I need it about 10 below ambient for ales and it seems to hold that fine. Since I have extra wood and all the other parts, I'm thinking of building the larger version that will hold 2 fermenters as the space for only 1 in my current chiller is very limiting. I'll eventually get a chest freezer/temp controller later on, but this is a cheap alternative until then.
Just some thoughts and good luck!