I’ve been wondering for a while now what would be better when using PHP with URL rewriting:
Currently I always use the first format because I like that the best, but are there any advantages to the other methods I should know about?
I’ve googled it quite extensively but couldn’t find a straight answer, so I just wanted to know what you guys think 
Personally I have no problem with the
domain/folder/filename.ext
format. But that’s how it all was back in the day. Now many if not most sites have the “clean” “easy to use” “friendly” URL format.
I’m not sure about the trailing slash bit, but I’d also like to hear opinions on it.
Every time I think of the forums right here on SP the first URL that comes to my mind is “www.sitepoint.com/forums”. Not sure if that helps any. I just have a hard time thinking that your common visitor is immediately going to think about “www.blah.com/whatever.ext”.
Can’t you just apply conditions to handle the other scenarios?
I use both one and two ScallioXTX, I ensure that the end / isn’t required (?/? in htaccess) as people may forget it (and people may add it if it should be omitted).