Have owned both and prefer the 4pc as I feel it’s ever so slightly quicker otherwise they felt identical...they were both the older CTS versions...I still have the 4pc and fish it all the time.

How dramatic was the difference? I saw on another thread where you called it a "different creature." Just curious what you meant by that.

Glacier,

I have both the older 3 piece and the last version of the 4 piece. I have not handled the newer FastGlass II rods, so don't attribute this to that line. As for the older 3 piece vs the 4 piece, I find the 4 piece to be noticeably stiffer. I use two lines on these, mostly, a sci-angler shooting head sink tip and a heavy full sinker. On the 3 piece, these lines give her a deep and smooth flex when casting it throws the line very gracefully after some short false casts and a double haul. With the 4 piece, the feeling is much stiffer and the flex is no so much, but although it does feel that way, the 4 piece LAUNCHES both those lines several yards farther.

magicmike nailed it. The three piece is more “trouty”. I like that description.