Playing one ball is important for beginners. Pick a ball and stick with it all, or at least most, of the time. You will find that the rollout on the greens, and feel off your putter, are more about your swing than the variance between balls. Being a ball **** makes it hard to get consistent. Although there may not be one "best ball" around and on the greens, ball are very different. A beginner should eliminate variables not add them. Seems many begins think that because their swing is inconsistent, the ball doesn't matter. While that be be true most swings, it is not while putting and within 20 yards of the pin.
If you swing speed is 90MPH or less with your driver, give a long look at the Srixon Soft Feel. Does everything well except spin around the green. But rollout is predictable and it launches nice and high (a desired bonus for most beginners) yet holds its line in the wind pretty well. Does not fit my normal game (too high and too short with a 103 SS) but I play it in cold weather and the lower compression and soft cover make it respond like I'm playing in warmer weather. Feels great off full swings when it is 40* outside and always off my putter.