I don't have a dog in this fight (I have an a300 and a Benelli Supernova) and they, (SBE3 and a400 XP) are both better than my guns. The SBE3 doesn't feel as good in the hands to either of us. The owner has done some jerry rigging to fix the grip angle(he has tried all the shims/adjustments already) and it still doesn't feel quite right. The a400 Xtreme Plus(keep in mind it is not a regular a400) to me, feels better, swings better, and feels like the recoil system works better. I also love the oversized controls on the a400 X P. Of course, you can add those to any gun for $150 or so.
Everyone's got an opinion, I would try them both out. If I were picking between me and ilovesprig for an opinion I would go with his