Okay. I've met 3 people who I knew online. One of them, well, it was just a stupid decision. But it was a learning experience. The second one I went out to visit twice. He remains a really good friend of mine, and I'm glad to have met him. I wouldn't be surprised if we have the chance to hang out again.
The third ended up becoming my boyfriend. We met here on TFP and he offered to take me on a date when I was in his area for a concert. We ended up getting along very well, so we pursued a relationship that is still going strong after 6ish months.
As for the people being similar... it's a toss up really. It all depends on how you act online. If you're just as you are in person, then you should be fine. But it can be a bit awkward. It might take awhile for you to be comfortable with him.
So anyway, if you want to meet him, then go ahead. I'd suggest staying in public places, but I didn't exactly follow those rules, so just trust your gut and get out of there if the guy seems like he's a bit instable...
Also, discuss any expectations you two might have. He might be going into it lookin to get laid, and you might just want to get a cup of coffee with this guy you chat with. Or vice versa