I'm also a first time chameleon owner only because my bf bought ours at a spur of the moment thing, not the greatest thing to do considering we hadn't done any previous research about them. Regardless of the random decision, we bought everything we needed for her. (Bought her from petco) I dont have exp with the other species although I have seen them, I still fancy veilds. Just just like their overall sillouhuette and look.
I would however, suggest you get a male first as they have less things to worry about, (ie eggbinding, lay bins, etc) as well as a longer lifespan. Never had an issue with her being aghressive as of lately, which could be for multiple reasons, but she is generally a sweetheart. Our juvenile male, Zeke, isn't as timid the more we handle him.
So far I feel we have been doing a great job keeping them happy and healthy to the best of our abilities. I didn't find it difficult to cater to either of them. Zeke, being a male, did seem more 'aggressive' than Cami, but I have my ways of getting him to simmer down.
Another thing was... They are a lot cheaper than the other species. ;p But if money isn't the issue then its all on you. I do like the vibrant colors of the panthers but the veileds patterns suffice as well. Oh yea.. And veiled males obv have more color than females. Hope this helps!