I think this is against the stereotype, but I'm the middle and I love it. I can't say I always did (I'm sure I had an agnsty phase in the teen years), but now I think it's great. My relationship with my older sister is very different than the one I have with the younger one but they're both really fun and rewarding.
Plus, I have spent a LOT of time just kind of flying under the radar which is great.
I think I was an anomaly. I'm the middle, but didn't feel like much of a neglected middle child. I think I was more extroverted than my siblings so I never felt lost in the shuffle, I took more of the lead in many things.
I am the middle child (share with only brother) but really have no major complaints regarding older sibling but younger two got away with a lot more! It helped them tremendously that my parents had more money after I left the house but they are spoiled!
DH is a middle of 3 and is the stereotypical middle child, older sister is a train wreck and younger brother can do no wrong as he joined the army and had first grandson. DH flies under radar and is the "bad" son who refuses to move closer to his family (thank god)
I'm a middle child, and yes, there were differences while growing up between my sisters and I. It wasnt horrible, but it was there. Example: my older sister got away with a lot, younger sis was (and still is!) spoiled. I don't fault them for that though.
I have three kids now and I try to make sure the middle doesn't get treated differently. DH likes to say I play favorites with her, but I dont think so. I just connect differently with her since we both hold the same birth order placement. You know what though? She is almost exactly like me too, in looks and personality, lol!
I wanted to add that I too tend to fly under the radar a lot. I'm also the most laid back, mellow and quiet of the three of us. And I was always the one blamed for things I didn't even do as a kid!
I have fun with my parents though, as I like to joke around about being the poor middle child sometimes. It's all in fun though and they know it.