Its just my personal pref.... I like the way the diamonds sound more then the rainbows. The rainbows seem a bit dull and quiet for my liking. They sound better then most speakers out there i just like the diamond speakers...
if you're going for 'entry level' then give the rainbow soundlines a try. i ran a set for awhile, and loved how they sound. but i high suggest getting a dedicated amp for them though. it doesn't have to be powerful amp...the soundlines doesn't take much to get loud and clear.