I choose a veiled after doing research and seeing they are one of the hardier species and can be more forgiving for a beginner keeper.
Is he a good pet? Yes and no. No, because he absolutely hates me since I am the bad guy who had to give him meds a while back. Now, anytime I open his cage, I get a mouth full of teeth coming my way. But, when my girlfriend opens his cage, He comes "running" to her so he can climb on her shoulder or head and chill. They can have interesting personalities.
Yes, because they are interesting to watch grow into adults. With each skin shed you see a change in color and pattern, from the bright greens of a juvenile to the dramatic yellows/blues/greens/blacks in the adults. Learning about these creatures is another aspect of keeping that I enjoy. Anytime I see a new behavior or notice something that the cham does, I find myself googling the behavior of on here searching.
If you are prepared well before receiving your first came then unexpected problems will be minimal. Proper enclosure with plenty of foliage to hide in and various vines of all thicknesses, proper lighting with UVB and basking, supplements, feeders and gutloads for feeders. Write down a schedule that you can keep to for feeding, supplements, and cage maintenance. The cham will get into a routine and will hopefully be less stressed out once they get into said routine.
Keeping the cage clean is another big thing you can do to prevent any bacterial or fungal infections on the chameleon.
One thing that I underestimated about these chameleons is how fast the grow... I bought my veiled from FLchams with an approx. age of 3-4 months old. He is now about 11 months old and already in his adult cage. I started with a medium reptibreeze cage which measured 30" tall x 16" wide and deep. He outgrew it quick! After about 4 months in my care is when I started to notice him trying to wonder out of his cage more often and just started looking cramped in the cage.
They can be difficult to care for but once you have an understanding of what to do and why certain things are done it get easier. Hydration is a big thing some new keepers dont understand fully. I've seen some people use a fogger instead of a mister because they think the misting is for humidity. Then they are wondering why there cham is dehydrated and not drinking from the water dish... Not even 10 minutes of google searching will explain how they most likely will not notice standing water.
While I'm on the topic of misting, Invest in a Mistking system or Climist system!!! I wish I did when I first started. You can program the system to mist when you want and for how long which makes it easier for you in the long run. Instead of remembering when to mist the cage you just have to remember to fill the reservoir every day or so. I went the hand misting route at first because it was cheaper... I regretted it after the first week of keeping my cham. It was annoying having to run home on my lunch breaks just to mist the cage or making sure my girlfriend was home to mist while I was at work. Now I dont even think about it.
One last thing, Find a reputable exotics vet near you. In the health section of the forums there is a stickied thread with lists of many vets that treat chameleons throughout the US and other countries. It might take sometime to find one in your area but its best to have the info just in case something were to happen while you are caring for your chameleon.