I've never raised bobwhites but I've done a lot of reading up on them and I would say Bobwhites are significantly more difficult to raise. They bite really hard and they are more difficult to grow out in colony pens around mating season.
Coturnix are extremely easy to raise and they mature in about 8 weeks. Bobwhites can take over half a year to mature and the larger varieties like the Butlers can take about 2 years to get to full size.
Coturnix also lay many eggs, I get about an egg a day with artificial lighting even though it is winter. Bobwhites only lay eggs when it's in season although I've read a few reports of people getting offseason eggs from their Bobwhites.
If you are new to quail, Coturnix is a great way to get into the hobby. They are an extremely rewarding bird to raise.