Getting Ubuntu on some sort of tablet shouldn't be a problem in the long run, but the musescore program doesn't look ready for prime time to me - in the first example on that page, the spacing of the two eighth notes after the bar line is wrong; the appogiatura knocks them out of place; also the treble e" and bass d' should align, but they don't. Also, the slur from the appogiatura to the e" is not the right shape; the older versions of Finale also had this problem. (Also, there's supposed to be an appogiatura on d" going down to that last c"-sharp, but that's not the fault of the program).

Finale and Sibelius, as expensive and clumsy as they are (Sibelius is a lot less clumsy) get these things right.

This bit of persnickity nit-picking brought to you by Dr. Gecko, Ph.D.