Not tried Sagami but have tried Okamoto 002 - very tricky to get on. Squash my bell end (resulting in reduced sensitivity), horribly tight around the base and had one fail (shred) when fucking a gorgeous Ethiopian lass

Result was 6 weeks off punting while getting tested for absolutely everything on return to the UK. Yes - it was all clear.
My preferred condoms are Skyns large though have to be careful as I leak lots of pre-cum and they can get very slippery inside (risk of coming off though one has not done so to date).
EDIT: I find that over tight condoms give me willy wilt.