While I have such love and nostalgia for the '88 series and all of the original designs, the action figures didn't age as well for me. I collect several action figure lines and appreciate the advancements that have been made in the design/manufacturing. the 2003 line and 2012 are my personal favorites due to their more accurately resembling the animated characters they're based on.
I really want Playmates Toys to re-release the Fast Forward TMNT as well. Not so much the side characters as those weren't the best imo, but definitely the four brothers.
Edit: Looking at my TMNT collection, one would think that the original line is my favorite.
I absolutely love how Super 7 took those designs and added articulation and additional paint apps.