I've not heard of any specific issues with the rMB as yet, apart from a few unlucky people who've had hardware faults of different kinds. But nothing out of the ordinary from what happens from time to time with any computer you could order - stuck keys, battery problems, RAM failures, kernel panics. I think it's too early to tell if there's any kind of recurring defect pattern specific to this computer, and there may well not be one anyway.
As for cons, in my opinion you pretty much already highlighted the two main ones - lack of ports and price. For some people the new keyboard design is a hurdle as well, to varying degrees. Some hate it, others don't love it but are OK with it, and still others really like it. Me personally, I found it weird at first but haven't had a hard time getting used to it and I'm now starting to like it quite a bit. The lack of ports question is a big one for some people, but really you're the only person who can judge if this is a roadblock for you or not. But the price I think is something that everyone has to think about seriously, unless you're someone who can just buy whatever you want whenever you feel like it. One review I heard (on a podcast discussion) gave a pretty realistic assessment of the price, at least for the base model. When you take into account the retina display which is probably the best display available in a computer of this class, the extremely fast integrated PCI storage, the 8GB RAM and other factors such as the very high build quality, good battery life and no fan, the base model price is quite reasonable. Some people disagree with this because they would consider the CPU as quite inferior to what you can get for similar money elsewhere including in Apple's own range. They might also say that it's a joke to sell a machine in this price range with only one port. But I think it's a mistake to assess this machine on a simple bang for your buck scale, and even if you do, the base model has enough technical boxes ticked to make it reasonable to not be under $1000. At least not yet.
The value for money factor becomes a bit harder to judge when you look at the top spec model, because then you enter into territory where you could easily buy a much more performance-oriented machine for the same money. However, at that point you're either looking at a machine that is nowhere near as portable, or you are looking at something a bit faster like an Air but with a very disappointing display compared to how beautiful the rMB's display is. Arguably it's not just a more beautiful display but it also makes the machine far more usable in meaningful ways for a lot of people.
Ultimately it comes down to what features are the most important to you and what you feel is an OK deal for the money you're spending. Coming from a 2010 MacBook Air, I think there's absolutely no reason to worry that the performance would be a let down, in fact I think you'd find it to be quite the contrary. Don't underestimate the extremely fast PCI storage - it has a huge impact on how fast the computer works. And also don't underestimate the display - it's really a massive improvement from any Air including the current ones, so this will be a huge upgrade in general to how you enjoy the computer in every way from writing to internet browsing to watching movies. Also another significant upgrade that you don't see written in the specs is just how vastly improved the speakers are. If you like watching movies or series, or listening to music while you work, it can't be overstated how shockingly good the speakers sound for a machine of this size. So if I were you, I'd forget about concerns that it will underperform compared to your Air - remember - in performance terms, just because you see "1.6" vs "1.1" for the CPU does not mean that the bigger number is faster, too many other factors are at work. The more important things to think about are how much you want to spend and whether the display and other things mentioned above are of value to you or not.