Depends on what how you plan to use them. Generally, the more use you expect, the farther toward cartos I'd lean.
In other words, if you're stocking up for a 4 hour road trip and want something that tastes good with no effort, the CE2s I've tried fit that bill nicely. On the other hand, if you're looking for something to use every day driving to and from work, I'd go with a quality regular carto.
The CE2s are awesome until they've been refilled a handful of times. Then the heating element is crusted up and you'll need to spend 15 apiece disassembling, flushing, dry burning, and reassembling (or just accept that any flavor you put into them will now be 'burnt'.) As far as I can tell, they're impossible to kill through normal use, but I personally am not all about devoting half a day to cleaning a week's supply of them.
A good regular carto will last at least a month if you're only filling it up once per day (I get a week out of each one filling many times per day) with little to no loss in flavor or performance.
