There is no proper comparison between a 70cc and a 110cc.
It all epends upon what u are looking for? If ur very strict on budget and bearing fuel costs is a problem, then theres no alternate to trial and tested durability and low fuel consumption of a CD70... but if u also want to add power and comfort but are ready to sacrifice a litle on the fuel consumption then Rider or pridor are good options.
Comparison of fuel consumption at ideal conditions on a long route...
The slower you go the more powerful engine of raider/pridor will give u better milage..
The faster u go, cd70's engine starts eating petrol and equals down to the economy of a 100-110cc bike.
But the maintinence sost of 100-110cc are significantly higher than a 70.