Cheap DAC vs. Cheap Audio interface (ESI DR. DAC NANO VS. MIDITECH AUDIOFACE II)

that probably would boil down to how cheap, but in essence I'd say that a cheap soundcard would need to do more than a cheap DAC and therefore would probably require more compromises.

Having said that it could well be that there is a chip out there that does all for a reasonable amount......it's all down to how much soundquality you want vs how much it is worth to you...

I havn't heard either of them, but the Miditech has an analog volume controller. In this price range thats quite unique. It could be a source of problems in the future (mechanical noise!). But it is also a much better way to preserve resolution in audio reproduction than a simple (=digital multiplier) digital volume control. 

It also depends on what chipset your laptop is using.