My daughter is big enough to use a full size violin. Excepting tuning with the pegs part, the transition is a very smooth one. I don't like four fine-tuners on the tailpiece. They looks ugly and add unnecessary weight to the tailpiece, which may dampen the sound. Finally I decide to give the internally geared pegs a try. There are two products in the market - the Perfection/Knilling/Pegheds pegs from the States (they are the same thing marketed under different names) and Wittner pegs from Germany.
The Perfection/Knilling/Pegheds and Wittner have different gearing ratios: 4:1 and 8.5:1 respectively. The difference is not as big as it sounds. I have tried both in real life and found them equally functional. I slightly prefer the Perfection/Knilling/Pegheds as they look more pleasing to my eyes and are a little lighter. These pegs look exactly like traditional wooden pegs. Without close examination you cannot tell a violin with planetary pegs from one with wooden pegs. They work most charmingly and make tuning a completely effortless, almost joyful thing to do. Installation is easy. All that you need is a reamer, a small saw and a piece of sand paper or a file. It took me less than 2 hours to finish the job, and that includes the time going through the detailed installation guide, which is available online here. Living in Hong Kong where relative humidity can rise from below 50% to over 90% in a day, these pegs are godsends. They are especially useful to children who don't have the fine motor skill and physical strength to turn traditional wooden pegs. Will they cause any damage to the pegbox? I don't think so. The friction and tension caused by traditional pegs probably exceeds that caused by these pegs. At least there is no erosion of the wood from constant turning. If known violin makers and collectors like David Burgess, Michael Darlton and Giovanni Gammuto say they are fine, I bet they are. See the discussions here, and here if you are interested.
By the way, violin shops in Hong Kong don't carry these pegs. I got my set from Gostrings, which I cannot recommend highly enough. Their price is unbeatable and their service is simply superb.