I have one of each and there both great releases. I think the 2.5 feels a little more precise and the safety is quieter.
Thanks for infoI used to have one and while I love most Carter Releases I preferred the Tru Ball Sweet Spot over the Solution 2.75. I found that the Sweet Spot was more consistant on firing, where sometimes it seemed like the 2.75 just didn't want to pull through instead requiring me to rotate my hand. Its been awhile since I sold mine and I kinda would like to try it again just to make sure of my past experience with it.