3-ring is so much easier to work with. I've only used post-bound a few times, for gift albums, and I've hated them every time. The 3-ring binders make it easier to add and rearrange pages, and there's plenty of "give" so that lumpy pages can have their own space. They also hold a lot of pages without the hassle of messing with posts and spacers.
The Keeping Memories Alive albums are very nice. They don't look like office binders at all. The covers are nicely textured, padded faux leather and they have finished metal corners.
The page protectors you've been using with the postbound albums will be too long, because of the extra strip of width in them that allows them to (sort of) lay flat. I like C-Line and We R Memory Keepers page protectors. The American Crafts ones are nice too, very roomy for lumpy pages. They cost more than the Dollar Tree ones but I think you'll find they're a lot sturdier. (I bought the Dollar Tree page protectors once, found they wouldn't fit in my albums, and didn't like their flimsiness. I cut off the strip with the holes and use them for storing paper scraps.)