There is also nubits, pegged to usd.
Indeed.
The only thing is that Nubits has a bit of an ugly pegging mechanism whereas Bitshares has a very elegant one. (I say that as a 'scammed' investor in Bitbay which uses the Nubits approach. I'm still hoping Bitbay might get somewhere).
The thing I like about Bitshares is that it simultaneously offers two distinct types of investor exactly what they need in a complimentary way. The commercial world which is looking for a stable currency will buy the bit asset (e.g. BitUSD) meanwhile the risk-seeking investment sector buys the underlying collateral (Bitshares / BTS). The more adoption of the pegged asset there is, the more value is gained by the collateral (BTS). The less adoption less BTS value, but the whole time the Bit asset remains pegged even though the BTS collateral valuation varies.
There's also no limit to volume as their is with the Nubits approach - in fact the more BitUSD is adopted the higher the value of BTS goes. This model therefore stimulates BOTH supply and demand at the same time.
The NuBits model on the other hand only concerns itself with throttling supply in the hope that there will be enough prevailing demand to make the price rise. It's a one-dimensional model as opposed to the more holistic BitShares approach. You're basically just volume for value as opposed to creating an asset which the market naturally pegs through the interplay between those two distinct trading groups I described above.