I can speak for Boston - s/t. Personally, I love the album (but mostly due to nostalgia). The album is great at first, but it does get old pretty quickly. So, the final decision would be if you liked "More Than a Feeling," then go buy the album, since most of the songs sound pretty similar to it anyway.
big Madge fan, I absolutely agree with Henrik (and whoever else said it) that Like a Prayer is her best album- for me, it's that and Ray of Light, but I have to give LAP the slight edge. Great themes, and it's one example what sets her apart from her contemporary pop females. It's even classical-sounding in spots. The transition from "Dear Jessie" to "Oh Father" is one of the best I've heard on an album.