The original turtles was/is one of my all time favorite cartoon series. I was a huge Mikey fan and even broke him off in to a little "series" of his one that I called the Radical Squadron(this was year before Swat Kats), it was similar to Marvel's Secret Wars mini-series in which the Fugitoid tried to beam the Turtles to this Alien world that was in desperate need of heroes, but in stead of Leo,Don, Ralph and Mike, he got Mike, Ace, Genghis Frog and Mondo Gecko and Metalhead and now the six of them had to save this world from evil and find a way back home(I'm amazed I still remember all of that)
Ace was and still is one of my favorite figures, I always saw him as sort of this tough as nails type of guy who had a big heart but didn't show it much. I figured that he probably missed being human and although he was happy with his friends their was something missing in his life, that he could never get back.