Man nobody ever gets involved with these.
Olias of Sunhillow is an enjoyable record from beginning to end and it really is in a world of it's own. Jon has some good stuff with Vangelis but it doesn't compare to this IMO. I can't think of any Yes album to compare it to, but it does recall some of the weirder moments off of Tales.
I voted good, but I would have voted for great if it was an option, I wouldn't call it brilliant because that's a word I reserve for very few albums. It's certainly an acquired taste and even being a Yes fan won't guarantee that you'll like it because it's a really out there record. It's hard to recommend an album like this because I can't think of anything to compare it to, you'll just have to check it out for yourself.