I haven't found this in Canada, so on a recent trip across the border, I scooped one up from Target. Judging by the reviews, it seemed worth a try, and at $11.99, I had little to lose.
For my very golden NC25 skin, I chose Nude. It's a very good match, yellow enough to satisfy me. It's very lightweight. The first time I tried this, I was a little put off - it seemed streaky, didn't apply evenly, and barely gave me any coverage, despite reports that it could be layered. It might have just been me that day; I gave it another try the day after, and this time, it applied like a dream. It still gave me sheer to medium coverage, but when I very lightly dusted MAC Mineralize Skinfinish Natural over it, wow - perfection.
While it's a really nice finish, it isn't budge-proof. Where I'm oiliest (around the sides of my nose), it disappears after some time. I have to touch up there with concealer, and then I'm good for the rest of the day. This formula seems to me what Photoready should have been - while I like Photoready enough, this gives me that candlelit effect, in person and in photos.
Now, about the comparisons to Nars Sheer Glow. In my opinion, and experience, Sheer Glow allows for more buildable coverage, as it's just slightly more opaque. Sheer Glow also has more staying power than Healthy Skin. Healthy Skin, however, looks more natural, although Sheer Glow will accomplish the same look if it's applied very thinly and with a stippling brush. I like both; I just happen to match Sheer Glow better, as it's more yellow. But I'll keep Healthy Skin in my arsenal. It's worth it.