Hi!
1. Pro for the 5 years, it's less "paper work", due to proofing things about your marriage if you do the 3 years.
2. No one asks about the tax transcripts anymore.
3. I just attached my current green card, and my marriage certificat as evidence of name change, that's it. If you ever got a traffic ticket, you have to attach the proof that you paid for it, I think. And if you pay child support, you have to show proof of that.
Good luck! I went with 5 years, even I got my GC based on marriage 15 years ago, and just left the US once in the past 5 years.