Q Post connected is not cheaper rather costliest service. They calculate on volumetric weight. So logically it will be better only if you are shipping stones...
I have used their service only once and will never use it again.

The original weight of item was max 200gm (T shirt), Based on their calculation of volumetric they made it 2.5 kg, so they repacked it and made it approx. 1.5kG and added repacking charges.

Ultimately for 200 gm product I had to pay approximately 200 QAR, which is real costly. Be aware of this QP-Post connected,.

I am using Aramax, so far their service is the best and comparatively their charges are ok. At least they don't charge on volumetric basis. and service is very quick.