From a news story titled "Report: Low-Cost Airlines Perform Better
Low-Cost Airlines Provide Better Service Than Traditional Carriers"
Newer, cheaper carriers like JetBlue and Southwest were more likely to arrive on time, according to the report being released Monday. They were also less likely to mishandle baggage, bump passengers or generate complaints than their network competitors
.....Southwest, with 0.14 complaints per 100,000 customers, consistently generates the lowest complaint rate in the industry, the report said.
Continental and Northwest were tied for most complaints, 0.95 per 100,000 customers.
This study can be misleading because Southwest (not sure about Jetblue) does not interline any bags. With out that level of service comparing LUV to NWA and CAL is really unbalanced just as is the on time issue (LUV does not use ACARS for time reporting). The "newer, cheaper carriers" have a very different product than airlines such as NWA and CAL. LUV and JBU are point to point were NWA and CAL codeshare so the shear volume of bags being moved worldwide is much more complex than that of a point to point carrier that only moves bags on their own network (one could argue that that SWA and JBU with only a point to point system should have minimal to no mishandled bags) ..... my opinion..