@Livelovedance - here's a quick example assuming you have a CSR:
Southwest has a flight I'm looking at right now for $142.98:
1) you can book it with 8,619 points (and you owe the $5.60 tax).
2) I'm not 100% sure how URs work with SW but I'd assume that flight would cost 9,532 booked with URs and (I'm assuming that you then DON'T owe the $5.60). So you spent 913 extra points...which is worth $13.70...now you can earn RR on the flight which gets you 719 RR points. Those are worth about $11.60...
END RESULT: So somehow you net the $13.70 with the $11.60 and compare that to the $5.60 you spent and I guess you could argue that URs are actually
SLIGHTLY better (i.e. by $3.50) BUT the flexibility you have booking with RRs is UNRIVALED in the frequent flyer program space in my opinion and that's why I'd give the advantage to using RRs.
Hopefully this helps - or maybe just made it more confusing haha!! It certainly confused me for a minute comparing the too. If you don't have a CSR there is NO WAY that booking with URs will beat transferring to SW RRs.