This jacket is amazing. Schoeller's C-Change fabric has an amazing feel/finish and is completely waterproof.
No taped seems, but I've been in and out of downpours and have never had any water come in. The RiRi zippers are another awesome feature, which should be labeled 'built to last.' Bottom action zipper is also nice for venting and accessing the jersey pockets.
Lastly, The S1-J's winning move for me is the fit. Until owning the S1-J, Ive never had a jacket fit me properly. This jacket really has a click-in 'racer/slim' fit, no flap to be found.
Buy and be happy.