Use a demonstrative pronoun only if the connection to the intended antecedent of the pronoun is quite strong. Otherwise, your pronoun reference may be too broad, thus unclear.
The sophisticated computer sound system lets the user input pitch and duration from the MIDI keyboard. This facilitates musical transcription.[Does this refer to the sophisticated computer sound system, to letting the user, or to the inputting of pitch and duration?]
Sophisticated computer sound systems let the user input pitch and duration from the MIDI keyboard. This direct input facilitates musical transcription.