The comments that are here are correct. One of the most important is going to be record keeping. There are many commercial operations that keep better records than registered owners do.
One of the things with registered cattle is an opportunity for selling bulls. But with the prices that feeder cattle are bringing today one really has to decide if it is worth the extra cost to raise breeding bulls. Maybe with prices being so high, breeders will be more selective as to what they keep for bulls to sell.
As for selling breeding stock heifers or cows, quality animals commercial or registered will always sell well. With registered animals you have a smaller market, with commercials more producers may be interested.
Above all, whether you are commercial or registered, you need to have a quality herd.
We have two registries, Composite Beef Cattle Registry
http://www.compositebeef.com and Composite Dairy Cattle Registry
http://www.dairycattleregistry.com With our beef cattle registry, you can start from commercial animals and grade up to a registered herd, (many other breeds also allow for this, but some breeds have closed herdbooks, example: Angus and Hereford). Our dairy registry, again you can grade up to purebred, we represent many of the non traditional dairy breeds, Fleckvieh, Montbeliarde, Norwegian red, Red Dane, Swedish Red, and other crosses that producers want to register and identify the ancestry.