Fred,
The Plinius is the cream of the crop you listed IMHO. I have a friend who owns the 8100 and I previously owned an 8200. They were both recommended by another friend who uses Audio Research tube amps, so you know where the recommendation's coming from.... Really good amps. The Arcam is also probably pretty good. I owned an Arcam Alpha 10 and there's one for sale on A-goN right now for a decent price. It was a good integrated amp and I enjoyed it. But it's not as good as the Plinius.
BTW, my current amp is a Rega Elicit-R Integrated. It's out of your current price range at $1500 +/- $200 used. But it's worth it if you up your budget.
The Plinius is the cream of the crop you listed IMHO. I have a friend who owns the 8100 and I previously owned an 8200. They were both recommended by another friend who uses Audio Research tube amps, so you know where the recommendation's coming from.... Really good amps. The Arcam is also probably pretty good. I owned an Arcam Alpha 10 and there's one for sale on A-goN right now for a decent price. It was a good integrated amp and I enjoyed it. But it's not as good as the Plinius.
BTW, my current amp is a Rega Elicit-R Integrated. It's out of your current price range at $1500 +/- $200 used. But it's worth it if you up your budget.