Well I didnt feel like reading all the replies I'll just give you my opinion. That enclosure would be the absolute min I would use for a JCP, bordering on to small. Its hit and miss on the aboreal qualities of JCP I have 2 one hides out most of the time the other perches occasionally. they only seem to be active in the evening/night(nocturnal).
My cornsnakes actually climb a lot more than my JCP as they have a lamp over some branches as a basking area.
I cant tell for sure by the picture but that enclosure seems to open from the top. That kinda sucks. The reason I say that is because you have to reach down into it to get you snakes out and with nippy youngsterst you ARE going to jump/flinch and you'll probably end up banging your elbows/bumpin the enclosure around. Also they are more of a pain in the a$$ to clean properly.
I dont really have a suggestion on what you should get but I would recomend a smaller rubbermaid enclosure for the first 1.5 years. It may not look as cool but I feel it would serve what ever snak you get better. In that time you could probably come up whit the 100 or so dollars it would cost to build a JCP a nice 4x2x2 wood/glass enclosure more suited to it. HetForHuman has done a really nice job of explaining how to build one here
how i build my enclosures.