Making nice recordings requires several things:
A) knowing what you are doing and
B) the right tools.

The biggest pitfalls are often not understanding:
1) gain staging and 2) mic placement.

Is it possible to get studio quality with these machines?
Well yes providing 1), 2), A) and B) are met.

To help with mic placement get some isolation headphones. They will cost you about 100 bucks. Also if you are using microphones understand that the acoustics of the space you are recording in will have a large impact on the noise going to tape. The type of microphone (i.e. dynamic or condenser and type of condenser) and the preamp it is run through will also effect your recording

Please be aware that professional recording studios may spend 4-6 times more than the cost of this rig on one channel of preamp and a U87 microphone costs about 12 times the price of this rig. Are these "high end" bits of kit essential ? Well no, however they do sound much better than a "bottom of the line" Behringer equivalent !