In my personal opinion the reverso when on belay makes feeding rope to your climber a breeze in comparison to the grigri. Rappelling with the reverso is also relatively simple and unlike the grigri you can use your atc to double rope rappel allowing equal force to be placed on both strands of rope. I defiantly suggest purchasing a prusik to double as a third hand though so that if necessary you can release the breakline and stay where you are. If you opt out on the prusik always ask for a fireman’s belay when on rap.
Although I love the protection and comfort the grigri offers with its auto lock, the grigri doubles in weight in comparison to an atc. Weight plays a huge factor in multipitching so being able to cut where you can defiantly matters. If your just starting out I would suggest the grigri over the reverso. As stated above the grigri makes belaying a lot more safer and relaxing as the auto lock does the work for you when catching a fall.