From what I’ve seen they’re on par with other $100 dacs, I’d personally suggest getting a separate dac due to the fact that you can upgrade independently. That’s personally what I did with my A3/e30 combo and I now have three amps and will be upgrading to the bf2.
E30 is a great dac and can suit you well up until you go for the ~$700 tier of dacs
Also, if you want to look at reviews of the e30, @WaveTheory did a really good review on it.