Just for the record, I have 0 issues with RT in terms of its OS seeing as its identical to windows 8 (for the most part). Its just with the atoms, they are the same price is the only reason I recommend people getting them. Once windows RT gets tablets in the price range of around 300$ I think it will be worth it, like when acer apparently said they are in talks with Microsoft for a 7" RT tablet. (It'll have to be around 200$ if it wants to do well though, 250$ would work too but no higher than 300). The issue is when the atoms cost the same amount and get like an hour less battery life,so I recommend people going with them.
In any case, I would wait for the vizio tablet just because of the fact that their ultrabooks seemed OK, but other brands seemed like they were better for the price. I am a huge AMD fan, but as of late, they haven't been able to get their TDP down to the level of intel, I think I read that the atoms get like 1.2 W TDP and the Z series is supposed to be around 4. If they can get this down, then yes, I would love to do some gaming on a tablet seeing as the atoms GPUS are pretty awful, I mean they do 1080p video just fine and that's about it. Yes, the amd processors do support more RAM seeing as the atoms are only 32 bit processors, but on these tablets, that won't matter for a couple of years just because windows 8 is so good with memory management anyways. Mine runs snappy on 2 gb ram. That being said, I always want AMD to do well because if they don't intel is once again an x86 monopoly and you know how that goes, they will stifle innovation and cost more. Good thing ARM is hot on intel's heels because while Intel can pretty much ignore AMD, ARM poses a serious threat for both of them. I heard rumors of AMD that they may make an ARM/x86 hybrid processor that could switch to ARM for battery and x86 for power. That would be awesome.
And for the Dell, you are right, the Qualcomm Snapdragons run circles around the Tegra 3s, I still don't know why MS chose the tegras for the surface as It probably would run better on a snapdragon. Mainly because the tegra 3's are last gen ARM CPUs. I really like the surface tablet, the build quality is immaculate: one of the best devices I've ever seen. I'm still not a fan of the covers though. If I bought a surface I would go with the touch cover because its seems good for a touch keyboard. I wasn't impressed with the type cover because it felt quite flimsy. I feel they should have made that out of magnesium as well. Also they key stroke and length were lousy IMHO.
So back to the dell: I would imagine their keyboard dock is probably one of the best seeing as their keyboards are fantastic on their XPS models (not so much on their inspiron line though). Yeah, I'm looking forward to it. I think at 599$ for 64GB without a dock is definitely asking for too much though, so unless they go on sale, they probably won't sell much. Otherwise it does look like a nice product. I've been liking dell hardware designs a lot in the past 2 years.