Only other deciding factor I could think of is if you ever planned to use a trunk-style bag. Might have trouble on the narrow topped blackburn.

But if you do buy the blackburn, go right to the nashbar site (I just did) to buy it rather than amazon. It's same price (24$), but if you buy 49$, you get another 20% off and free shipping.

Blackburn TRX-1 Ultimate Touring Rack

And no, no affiliation with Nashbar here, its just that I needed tires and ordered some and seeing your post and the price on that rack, I added one on, just because for $19 for that rack, I'll find a use for it.