I'll second that, but I'll give you my experience/opinion and let you go from there

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I had an RR which was totaled. The bags were fine as they were not on it.
The BMW cases are quite simply the best luggage on earth. The build quality and functionality is second to none IMO. I have owned/messed with three sets of luggage to make a comparison. Easy to pack, put on and take off, top notch build quality, best latches in the business.
I had a '98 Concours. Luggage was fine, not built as well as the BMW stuff, and the mounts were annoying. Leaked sometimes.
I looked at getting another '04 or later RR, but it wasn't in the cards; they all were gone time I got there

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I also looked at the Buell Ulysses and Triumph Tiger. The Uly luggage, made by HB, was IMO not nearly as nice/functional as the BMW stuff, although large capacity. The latches were chintzy and have a habit of failing if any force at all is used on them; plus the mounts are butt ugly and detract from the looks of the bike when they're off.
I bought a leftover '07 Tiger becasue I got a deal I couldn't pass on.The Triumph luggage looks nice and the build quality is close to that of the BMW, but they are small and the mounting system again detracts from the lines of the bike when off. the lock/latch/pop up carry handles are not as good as the BMW either. The sidebags look good great on the tiger, so I leave them on. With the topbox, the luggage system holds about the same amount of stuff as just the BMW side bags and is much more annoying to pack. The BMW bags are incredibly easy to take on/off. You take them off, pack, pop them on. You don't even notice the GS mounts when the bags are off on the BMW, they're engineered well to fit the lines of the bike.
The bags on my RR were from a well-traveled GS. I paid $300-$350 for them with the mounts, which also fit the RR. They had some scratches, kick marks, etc but looked fine. Places to look: here, ADVRider and ibmwr:
http://www.ibmwr.org/marketplace.shtml
I'll give you my opinion on the available R1150R (BMW) luggage mounts too. The GS mounts look the best, but you can't use the OEM R1150R luggage rack. You have to buy proprietry mounts for the RR which also have grab handles. I bought them and the rear luggage rack. I hated them. The luggage rack was stupid expensive and was useless except to mount the now-discontinued Pirate's Lair (Sargent) backrest. The OEM mounts killed the look of the bike.
To summarize, unless you want a set of bags that look brand new, there are deals to be had. I watch 1150 luggage that's in new condition go for 500-700 on eBay. I sold my luggage to a guy that bought a Rockster that was in the local paper (missed it too

) with Cee Bailey liners for $350. If I scored another R, I'd get BMW luggage w/ GS mounts, a Givi rear rack and top box. I'd remove the top box/rack/mounts unless I needed them. Hope this helps. All this subjective blabber, in one way or the other, is why everybody who has the Beemer luggage tells all the new folks to get it. It's that good.
Regards,
Jim