I'm VERY happy with my 5th (running strong, leak-free and problem free since June 2003- I think the Lizard Skin boot helped). It rides great, is light, and is very efficient. In my limited experience, the propedal damping just isn't as nice as SPV. It is just more low-speed compression damping rather than a threshold, after which you have softer damping. However, the one thing I really like about the RP3 is the ability to run it without the platform. That'd be nice on technical sections. I don't think it is anything worth spending a bunch of time and money worrying about though. Enjoy your Blur/5th combo. If/when the 5th wears out, replace it with whatever the latest and greatest is at that time- there'll probably be something better than the RP3 out by then anyway.
BTW- I'm traveling to the location in your avatar in a month and a half. Did you recently go there or something?