A re-read from my youth. I read this when I came out, which would make me five, which would explain why it had such a peculiar effect on me. I remember reading it really, really well...but as with all such things, the bits I remember are rather selective!
It's actually pretty good. That it's about twins separated shortly after birth is not that surprising - unless you're five years old and haven't encountered the concept of twins before (AND are an only child on top of that) in which case I can assure you it is MIND-BLOWING - and the slightly supernatural parts are delightfully eighties. You can virtually see special effects pencilled on in a couple of places.
There are some lovely details to the characters, and a welcome 'normality' to the families involved, but there's a lot of waffle about not much, and some really, really clunky plot device stuff.
It's still quite something to me, and I'd been worried it'd be plain rubbish. It isn't that, but it is unspeakably cheesy in places.