Is there anywhere you can still find a Gen 1? I can only find 3 and 4.
You can, if you look hard, but i honestly do not see the point. Gen 3 is a better platform IMO. I think Dan was saying it just to raise some pulses on here. Also if you have not shot both or either, do that; i'd say then you will not regret making your own judgment call. I personally do not like Sigs, as I mentioned before, but that's just my opinion. They are also bulkier and cost more. Even pricier places locally by us, like SSG tactical may have some used guns; worth checking if you want to save a few bucks.
Used gun wise, if you are contemplating getting one here are a few things to check for:
Matching numbers, test fire date and docs to include seller's id if private sale
Obvious damage (talking cracks in slide, receiver, bulges/rings in barrel, etc. vs. minor cosmetic stuff)
Worn out pin holes (repeated detailed dis/ass)
Presence of aftermarket parts
Dry fire, function check
Check recoil spring to ensure its proper and works (if doesnt go into full battery you d need to replace the spring assembly)
Make sure extractor is present and works; cycle rounds thru it if possible (dummy or live)
Check for damage on the breech face (hot loads)