decide how much power u want,,
from 70cc up to 150cc bikes are available,,
regarding ur question both are good,,
if u would be doing oly double sawari to go to univ and load some home shopping then 70 is best cause in city the roads are good and this is enough power,, in villages with unpaved roads and a lot of loading requires 125,, 100 is a cross inbetween,,
while u wont be enjoying a 70 to go to murree but a 100 will be pleasure,, a 125 much more pleasure,, but ads u go up in poewr more will be runing cost,,
so agar ap na srf uni ka lia laina ha tho 70 chonda la l (chinese copy of honda)
.. if u can afford initial cost and afterwards costs then buy 125,,honda 125,,
if u want something good in between the any 100cc bike wiill do,,
ud100 is very good bike itself ,,and above all its from a company that has a very reliable 70cc as well,, and the honda 125 has no parrallel in pakistan,,both quality and resale and performance wise,, but is pretty heavy on pcket due to low petrol average,,
how is ur daily travel in km?
so first decide how much is ur pocket and need then decide brand..