I have never served, but I have read some history books.
Like HH6 said, the embassy rescue by Delta failure was not the unit's fault, bad training by the Air Force and the plan was done by guys that had never seen combat. It was completely disorganized by the command structure. I call that one a wash as far as Delta's involvement.
Panama...again, bad intel. A lot of guys also landed away from the LZ.
Somalia...I don't think any other group would have made it out of there. Rangers proved themselves there, and the Delta operatives that sacrificed themselves to guard the downed chopper deserve mad props for what they did that day.
Again, I haven't served, but I do enjoy reading about history. I think our SOF guys really are the best in the world with or without a bias. I think the British SAS and German KSK are the only ones that come close. Considering Delta force is actually modeled after SAS.
What do you think about German Spec Ops HH6? Are they as well trained as they were in WWII?