I was so deep into buying those things, I'd take a NIB 550, PE90, AMT, whatever....and just shoot for fun[it never caused a loss]. I was paying 5K apiece for preban 550's in 1990. Paying 8-10K for some of the rae ones, made my friend's heads hurt. LOL! I bought all of them as investments, and it worked out marvelously. The same people who thought I was nuts for paying big loot for guns, have all freaked-out after seeing my 20-year return. The difference between a Swiss SIG and an HK long gun...is almost the same as the difference between a HK and an AK. Especially the 510-series rifles. Absolute pieces of art and mechanical marvels. The firearms being made now, no longer reflect the pride and engineering of those from Switzerland 30-50 years ago. Now, it's all just injection-molded parts and bean-counting quality.[damn the form, just need function] The biggest difference between collecting old SIGs and Hk's is.......having money, won't always find you the rare SIG stuff. Some of these are literally less than a handful around. I could never find or afford this stuff again.
I dig all the crazy tactical stuff out there, but don't see the money for what's being put into them. I had just about anything SIG that could be had/found. I made some great friends and met many interesting characters. I even had a contact who had a friend in the Swiss-Army, who got me stuff from the Swiss military as far as uniform stuff and small equipment.
I still like messing with the HK long-guns, and think they have always had the best pistols and subguns. In my mind, I think modern Sigarms stuff is about equal to the "best of the rest", of the moderately priced stuff on the market. I personally like CZ stuff a bunch more than modern Sig....though they're getting pretty proud of their stuff, since Angus came on board.