IMO handgun barrel length depends entirely on you... how well you've mastered handguns, especially the Contender.
I could hold and shoot a 14'15" barrel better than a 10" offhand, one or two handed, probably a product of so many years doing. Mattered not if it was scoped or with open sights (before the eyes started getting old). Nothing wrong with open sights if your eyes can still use them other than they will shorten the range you can shoot effective at. I preferred scoped as a 14" can come real close to equaling a carbine/rifle barrel in accuracy in the right hands, so your effective range is increased substantially. One of the reasons why so many of the 14" barrels are scoped, to take advantage of that whether shooting offhand or supported.
After trying them all I settled on sling carry for the 14/15" bull barrels. Bandoleers were the least desireable to me with any long barreled handguns, slow and a PITA to use; belt holsters meant always having to pull the pants up whether strong side or cross draw; in a hunting situation I certainly didn't want to give up a hand carrying it that might be needed to bust brush or catch a fall. A good sling system is hands free, puts the handgun where it is naturally protected by your arm/body, and is fast to bring into action with the added advantage of being useable for extra support shooting.
Both the 223 and 30-30 will perform very well in a 14", way better than in a 10", are not picky about ammo and the loss of velocity due to length verses a carbine/rifle barrel make little difference hunting when you know the ballistics of your 14" barrel and load. I've used the 223's for predator and varmint hunting (scoped), and the 30-30 barrels for years shooting IHMSA, some open sighted, some scoped and they were very reliable on the 200 yard rams with either sights shooting Creedmore postion (and well beyond when hunting).
So I wouldn't discout the 14" barrels... just another part of learning the technique for shooting Contenders. Decide what config you want, what you feel you will be the most confident with and you will have made the right decision "for you". IOW, confidence is 90% of the game, especially with handguns.