I have one of each of them.
Good concept, but not without problems.
If you even slightly bump the larger one at all the bottom piece comes unseated and you lose all your juice So for me it's definatly not one to carry around.
The smaller size seems to hold a little bit better.
If/when you get it I would suggest removing the top metal tube and filing the end that goes around the CE2 a bit, possibly even straightening it as it curves inward, I didn't at first and it was slicing through the wick the 1st time I put it together, but after I did that I had no problems with that.
Also with the twist on top you sometimes get that top silicone bit out of place, so make sure to check it so you don't end up with a wicking problem.