I ordered some and they do work fine on my MF batteries. I have been using three of them in rotation daily for a week and have not had any problems. No cracking, leaking, or funky tastes. Now as to my personal preferences/impressions, I did run into some problems. They are easy to fill. Pop out the cap with your fingers, pour in the juice, slide the cap back in. Easy as pie. Of course the easy out mouthpiece means that you can't just put it in your pocket (The cap will come off. Learned that the hard way.) They wick just fine, and without any filler the experience is similar to dripping, but if you puff compulsively (big hit, exhale, immediately puff again, exhale, do it again) it will lose flavor and vapor around the third or fourth hit. Give 20-30 seconds and it will be fine. I like to hold my pv's in my mouth with my teeth and because the cap extends a good bit past the end of the tube it feels awkward to do this (If you try to hold it by the cap, the cap will come off.) Lastly the center tube ( the airway from the coil) is prone to condensation. Not a big deal if you keep the battery a degree below horizontal when you vape, but if you point it up expect an ouch.
In conclusion, the main selling points for these is probably ease of filling and the purity of the flavor of your juice that you will get from it, and they are clear so you can see your juice level. It gives a completely different vape from an MF carto so don't compare it to that. I ordered five boxes. Am I satisfied. Yes. Will I order more, probably not, unless they discontinue CE2's. Hope this helps.