As a guy who makes (at least part of) his living delivering the Rapha Randonnées, I thought I'd pipe up to say that, in my humble opinion, the Rapha SuperLightweight Jersey is the best bit of kit they're making right now. Unless you want something that is in between warm & cool, I wouldn't even bother with the lightweight jersey anymore... the SL is THAT GOOD!
In fact, it's good enough that a customer on last week's trip through the Alps took my SL off me at the end of Day 1 and he wore it for all the remaining days. In fact, I never got it back... but, fortunately I know where to find a few more.
That said, the fabric is still pretty stetchy - this is definitely one of the things that I like about the jersey, but if you order a size that doesn't equate to 'race-fit', then it will likely sag down a bit when the pockets are full up in the back. I have my medium fitting snug, and with a guide's survival pack on board (large radio, camera, phone, park tool, two bars & two gels), everything still stays in place perfectly well, even when bombing down the Bonette for 25min!
Other bonuses of the SL:
- the rear pocket layout is normal - 3 pockets, plus one zippered
- the trim around the neck, zip & sleeves is perversely smooth & comfortable
- when you wash it post-ride, just roll it up in a towel and it's ready for day 2, 3, 4, 5 or 6
- perhaps the ultimate sin for Raphites, but the accommodating stretch of the fabric means sleeves can easily be rolled in the VERY high heat... just don't tell anyone I've done this.
In short, SL