Well, I have a uromastyx I adopted that has 3rd degree burn scars and is grossly over weight (still trying to get her weight down, but it's tough), and I have a bearded dragon that probably hasn't been fully healthy the entire 2 to 2.5 years he's been alive. Which reminds me. Make sure you get your reptile from a good source! I made that mistake with my bearded dragon and I'm still getting rid of parasites (though I think we'll finally be rid of them within the next month). The fat uro is so cute and really funny to watch. She just loves to waddle around. She has bitten me twice though. The first time was just because I was hand feeding her and she got into it, and she released as soon as she realized she had gotten more than greens (which was before she even left any marks or anything). Then another time I was putting her food bowl in her tank and she was in the mood for food again, so she apparently thought I wasn't putting her food in fast enough, and when I set the food dish in, she waddled on to the food bowl and gave me a little warning bite, much like the accidental bite. She wasn't trying to inflict pain. it might have actually been another feeding response. Either way, she has very strong jaws yet has never really used them on me. Apparently she latched onto her previous owner a week before I took her, but he deserved it. She is also touchy about her nose. I have to be careful if I'm trying to get stuck food or something off of her mouth, because sometimes she'll get annoyed and open her mouth at me. She's the sweetest little thing, but also a little devil.
That being said, my bearded dragon has never even attempted a bite. He's much more laidback in general. Not much more to say. A bearded dragon makes a good lap lizard, meaning they don't mind sitting comfortably with you while you watch tv or use the computer (when they're adults), and they are still fun to watch when they come out of the cage and run around. Inside of the cage they mostly just thermoregulate, run back and forth a few times, eat a little, poop every once in a while, and bask. Uros are much more energetic in their cages, though they have a tendancy towards inactivity during they day, preferring to hide part of the day and coming out in the morning and evening to eat and bask. though there are exceptions to that.
It's all basically your decision though. You have to figure out what YOU want for a lizard.