I was curious about Nubits since you keep mentioning it, found this article (although it is a bit dated, September 26, 2014) :
http://digiconomist.net/details-and-shortcomings-of-nubits/
Perhaps there has been some big changes in that time and the authors conclusion is no longer relevant.
"
Conclusion
In short, NuBits uses increases in its total supply (through various ways) and thus inflation as the only method to combat both an increasing and decreasing price. This might be able to hold for a while, but leaves nothing but a time bomb waiting to go off. The developers might have created NuBits with the best intentions, but until any adjustments have been made it is advised to avoid from this digital currency. A discussion on the discussed problem and possible improvements can be joined on the NuBits forum
here."
I can't tell you with certainly because I'm just a regular user of it, but I thought there was a "burn" element.. someone more familiar with it is welcome to correct me.
If you look at their forum, they seem to know what they're talking about. I've seen charts compared to other USD pegs and nubits did the best... bitUSD in the early days was all over the place, though I don't know if they fixed that (they use a totally different method.. again, I'm not familiar with the technicalities).
For a long time and on a regular basis, I've held a fair bit in nubits and I've always found it very reliable. There was one occasion I believe where it strayed to 1.09 nubits to USD but that really was unusual. Sometimes it strays between 0.99 - 1.02 nubits to USD but overall I'd say it works very well. In fact, in the past few months I'd say it's improved, but I have no idea why.
They're confident enough with what they have that they are launching the same thing for euros, yen and yuan (not sure which yuan). I find that very interesting.
If there was a DashUSD, we wouldn't need an outside exchange at all, the MNs would simply handle it all in-house. Or maybe - I'm not sure - create a new type of node that provides liquidity for an FX exchange to operate - an FX Node (FXN). If that's the case, it would expand the governance system and potentially make for a more democratic system.