These are single axle cams. However, they are a good deal lighter than the DMM dragons or the BD C4's. Also, the head is slightly narrower than that of an equal cam from DMM or BD so they will fit in more spots.
Not sure why or if it matters which cam is used. What matters most is climbing and staying alive. From my rack I only use Metolius cams to keep me plugged into cracks. Great pro, light and I can't stop thinking about them. What's really weird is I generally leave my mastercams behind too, this is unexplicable. So not sure why I don't fall in with the crowd and say that C4s are the best, I'm just not feeling them...although for offwidth I don't have many choices.
Super solid cam, great in the mid to larger sizes, the size 7 is perfect for hand/fist size cracks. After rotating out many different cams over the years these and the BD C4s are the ones that are consistently solid. Highly recommend them in the larger sizes.
These are nice if you are on a budget and can get them cheap, but I would recommend saving your money and buying the best commercially available cam - the Black Diamond C4. I don't have experience with aliens so I can't comment, but I've used BD, Trango, Metolius cams the most and I'd say Metolius is as good as any other second tier mid-large size cam, but can't stand up to the C4. Buy all of the TCUs and leave the power cams.
"Has its uses, doesn't compare to BD or WC"
I have size 1-4 ultralight 4CU and 1,2 old style TCU. Cons:The dyneema sling may have saved a gram, the thin sling (and not having it doubled over the stem like the old style 4CU/TCU) makes it very easy to bend the stem out of shape over a fall. The rangefinder feature is only there to get your cams stuck: if you ever place one in the green dot range, chances are you won't be able to get it back. The #4 is the most often piece on my rack to get stuck.ProsDouble stem cams can (and do) fit in some spots single stem cams don't. The lobes of the smaller cams are made out of harder 7000 series aluminum, making the lobes hold up better over time (and falls) than say the BD cams in that size.