I'm a king snake/milk snake guy, but I do have two pythons. One is jungle carpet. He's great. They are known to be nippy when young, but I was only ever nipped once and it didn't even break the skin. It was more of a cautionary "leave me alone" bite than anything out of real fear. They are easy to maintain (in my opinion easier than balls). And they eat. And eat. And eat. Mine is always hungry, and in fact, I feed him the leftovers when my other 14 snakes don't eat. Whether it's a pinky mouse or rat, whatever. He cleans up the leftovers. The one big thing to watch for is this voracious feeding response. Make SURE your pet knows that it's you reaching in to handle him and not food. As I said, I've only had one bite and it was a long time ago.
Carpets are very alert and mine comes out of his hide box almost every time I enter the room. He's a little jumpy if I don't support his whole body, but is otherwise as tame as my ball python. I even did a presentation at my fiancee's school yesterday and he was calm even around fifty second graders.
As far as speed, I wouldn't compare to either corn or ball. Think rattlesnake. They hit their prey fast and hard and it even impresses me sometimes.
I would recommend carpets, even for a beginner. The key, in my opinion, is to handle the snake enough so that neither you nor it is afraid of the other.
For some more information to a beginner's questions about carpets, I just made another lengthy reply to someone on the morelia forum. You might find some of that info useful.
Good luck!
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1.1.0 Hondurans Het Amel
1.1.0 Hondurans Anery, Het Hypo
0.1.0 Honduran Hypo
0.2.0 Pueblans
1.0.0 Pueblan Hypo
1.0.0 Thayeri MSP
0.0.1 GBK Blair's Phase
1.0.0 California King
0.1.0 California King Blue-eyed Blond
0.0.1 Speckled King WC
0.0.1 Jungle Carpet
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