Bought a couple of 3 packs very recently, replacing an older (and now leaking) Clearo. Hooked one of these up to my Mod after allowing about 5 minutes for the juice to soak in, and vaping away.
Easy to refil, lasts well, no leaks, and really great flavour and vapour volume.
Very useful, and good V4M for the use its being put too in terms of it's lifespan.
Highly recommend giving them a go.