In 36-60deg F weather these over-shoes have kept my toes from freezing on descents (I get numb fingers and toes easily). They're small enough to store in my tail bag when things warm up and they slip on easily without issue.
As far as being waterproof, they're good enough for anything except the really wet days. If you're going over big puddles it seems that water can splash upwards into regular (summer) road shoes. On days with light rain, steady mist, and gentle showers they have been excellent and kept my feet dry.
I was wanting a low profile, cold weather glove and these have fit the bill. I'd say on their own, they keep my hands comfy while on a decently strenuous ride down to about freezing, or low thirties with wind. Below that, I need to add some merino wool gloves underneath, and that keeps me warm down to about 20F. The gel is minimal, but better than no padding. I normally wear XL gloves, and was a little worried that XL in these might not allow me to fit a thin pair of gloves beneath, but that isn't the case. I also picked up a pair of the Giro merino wool gloves to pair with these, and they've been great mates for one another. From my experience, if you're peddling at a decent rate and getting the blood pumping, these gloves do well to insulate and protect from the elements down to around freezing. If colder, or you're doing a more casual jaunt, I'd expect needing a little extra insulation, or up the heart rate to get warmer. Otherwise, I see myself getting some good miles in with these in the shoulder seasons or in inclement weather. They're light weight as well, so no problem throwing them in a jersey pocket if the sun comes out.
So, I'm nearly bald. That makes keeping my head warm more of a challenge riding bicycle when the temps are in the 20's -30's.and the wind is gusting to 30mph. I've tried several options and I'm either too hot or too cold. The Castelli Difesa 2 Cap does have a down side, and that's it's size. It fits small at first. I remedied this by stretching the cap out quite aggressively without damaging it. This worked! It's now even comfortable with a thin skull cap underneath. As a reference, my normal hat size is 6-7/8, to 7. I'm glad I bought this cap. It makes all the difference.