I noticed this post is a little old, but since it is still active I thought I would try to add an attachment I got from a Steel City tech when I asked this same question. The rpm specs seem a little confused between the product info and the manuals. It is not clear whether they are for the motor or the cutter head.
I haven't decided on one yet. There are only seven customer reviews for the 40200H, and three for the 40300H on Amazon. The reviews are good for both, but several people note some tear out on hardwoods using the 400200H. This is not mentioned as a problem for the 400300H, but again, it only has three reviews.