I have 3 of the standard longswords. I think the link provided pretty much sums it. To answer your questions directly:
Compare to other paddeds? Don't know, these are the only ones I've used, and ever seen, for that matter.
Weigh/handle like real swords? The only example I have of a "real" sword is the one replica I own. It's a longsword made by a company called Arms and Armour that they named "Black Prince", they claim is based on an actual artifact (
http://www.armor.com/sword034.html) Without getting into a sword review, in my opinion it is a good representation, and is what I base my study on, and make any comparisons to. So, comparing the RSW padded to this replica, it is quite close in weight and balance. A happy coincidence for me, because the paddeds are off-the-shelf stock items. Handling...leads to your last question.
Can be used in place of waster? I would have to say (controversially) yes, but to a degree. All of the tools (swords, replicas, simulators--wasters, paddeds, steel blunts) have some degree of compromise when used, because they are all slightly different, and each one is used for what suits them best. It isn't hard to imagine, if you don't have a variety of sword-tools handy, that wood on wood is closer to steel on steel, just less dangerous, and that paddeds, when pressed together, will deform in the padding, and not behave like the property steel or the close substitute, wood. But, sometimes, when it looks as though when using the wood wasters, that I may hurt myself or others, I'll just switch over to the paddeds. Also, I've had some people want to try things out, but don't have a waster, they use the paddeds in place of the wasters, and it still works for basic learning. That being said, of the sharp, blunt, waster, and padded that I have, the waster gets the most use. The waster is like a starting point, and I'll adjust either way--padded in one direction, or steel in the other direction, depending on what I'm doing.