Picked up a few of the XL's a while ago... they've been great so far. When the wick starts to char (as it does over time) you can just take them apart and move the wick down to a clean spot... very nice.
The only major "issue" that I have with them is I'm using an eGo and the cone won't fit over them... I know that on the XL I'd still have about 1/2" sticking out of the top of the cone, but I just feel safer with the cone on there as the bottom of the clearomizers aren't solid. You can pull them out or they CAN (hasn't happened to me yet) wiggle out in your pocket. Modding the cone would be easy enough, but as I don't have a spare... I'll hold off on that for now.
Either way, great carto so far. The "wicking issues" only seem to happen at first... simple enough to tilt the PV to get the juice to flow up into the atomizer. After a while though, you won't really need to. It could be how I hold my PV when I'm vaping though. I always hold it horizontally and have the clearo rotated down so one of the ends of the wick is as low as possible in the tube so it always stays in the juice.
I've tried a couple other cartos and swore them off because of wicking issues, filling issues, and surprise burnt taste issues... these have almost none of those problems. The wicking issue is temporary (IME), they're super easy to fill (they might seem harder because of the syringe, but when you take spillage, mess, and actual ease into account; they come out ahead), and I always know exactly how much juice I have left in there.
Vapor production is pretty good with these... I'm coming off of dripping on LR's, but I'm still very happy with the vapor production on these. Coil life is pretty good as well... I've already had to move the wick down once from use and the coil is still kicking... I won't be surprised if I have to move the wick a few more times before the coil bites it. I'm moving the wick just to keep it on a clean section. It's not because I was getting any bad tastes though... even with the charred wick, I was still getting good flavor and good vapor. I just don't like to get caught by surprise.
On top of how well it works... they're around $10 for 5 of them (from where I order from). That's insane for me... I've been using LR atties for so long now I'm just used to paying around $5 per atty every week. To spent $10 on 5 and have 1 of them last me this long is mind blowing.