So what are QDROPS anyway

Description of qdrops in the ipsctl -a output:

Example:
ifphys:eth-s1p2:errors:in_qdrops = 315024

In_qdrops:
This will give an idea if the system is able to handle the packets received and keep up with the load. If the system cannot keep up with the load, then the descriptors provided to the MAC may not be getting serviced fast enough resulting in receive "No buffer conditions" or "No mbuf condition".
In simpler terms it is an indication that the Nokia Application Platform unit was not able to process the packets and hence they were dropped on the wire. This usually indicates that the box is under heavy load and ierrs drops are occurring due to performance reasons.