The advantages of R2R are small element spread, increased accuracy.
The advantages of charge scaling are best accuracy, no op amps.
On the contrary, R2R has disadvanteges as slower, sensitive to parasitic capacitance, nonmonotonic.
Charge scaling DAC has disadvantage as large area, sensitive to parasitic capacitance.
The choice is up to your purpose and design condition.
Both are having their own advantages and disadvantages. If you are going for high speed application, you can go for R2R method. Because it is less sensitive to parasitic capacitance.
If you need more details, don't hesitate to contact me.