Well Sprinter is a better choice simply bcoz it is a 110cc bike now quality i would say is equal i would rate honda a bit higher in terms of quality, design compared with ECO.. the sprinter original is better in quality i guess..
About switching to ECO yes u should bcoz i will do the same soon from cd 2006...
Economy sprinter will give u 60 and my honda cd 70 if set to good mixture of fuel also gives 60 if u want to get more out of cd 70 that means the mixture will be too lean and that puts engine under more pressure plus also engine runs hot..
My sugestion go for it...
BTW for how much r u selling ur 2006 CD ?