590A1 20" barrel, full length tube, bayo lug, speed feed stock, ghost ring sights, parkerized finish.
I love it. Never had a single problem with it. It is actualy pretty acurate with slugs, even with the smooth bore. At about 60 yds, it will keep them in about 3". Get one, you wont regret it.
Same for me: 590A1 20" barrel, 8+1, bayo lug, ghost ring sights, parkerized finish. Except I have done some slight modification. I have the Mossberg heat shield on there (yes, I DID get it on the A1), the Mesa Tactical Low-Tube adapter http://www.mesatactical.com/product_info.php?cPath=31_33&products_id=80&osCsid=42e1cad97d559171a483014888bcfbe6, and the Ace M4 Socom stock with the short picatinny rail behind the ejection port for my tac-light. Never had a single problem. A very sturdy as well as badass looking shotgun.
I used a 590 mariner for skeet shooting a while ago. Standard 20" barrel and 8 shot tube with marinecoat.
I shot my first perfect round with it. It wasn't mine and I had te return it to its owner, but I did manage to buy a mossberg 500 persuader (18.5" barrel, 5 round tube) and it works great.