Sizes and types
The Ukulele comes in the following sizes; Soprano, Concert, Tenor and Baritone. Each has specific characteristics that may influence a player to choose a particular size.
The soprano ukulele is an excellent starting size and introduction to the Uke for a couple of reasons. For one they are the least expensive and represent the biggest bang for the buck. Two, the soprano Uke, because of its scale length and string tension, has that Uke specific “jangly sound” most familiar to the average listener. It is tuned the same as the Concert and Tenor They make an excellent choice for children because of the size but are in no way considered too small for an adult. Most ardent Uke players own one or more.
The concert size (which is sometimes referred to as Alto) is larger and probably the most popular size among performing artists. It is tuned the same as the Soprano and Tenor. The larger size and fret spacing afford more room to make chords and the increased string tension make it harder to bend strings out of tune. Those with larger hands and bigger fingers will find the concert easier to chord than the smaller soprano models.
The tenor is the largest of these first three and is tuned the same as the Soprano and Concert but has more frets. This allows players to reach notes in the higher register. This size is a common choice for guitar players who are transitioning to ukulele. For the simple reason that they are used to holding a much larger instrument, the tenor is more familiar to them while a soprano might feel tiny.
Other than the much larger size of the baritone, the biggest difference from the first three listed here is the tuning. For the first three sizes use the standard tuning GCEA is used while standard tuning for the Baritone the Baritone is DGBE
You couldn’t make a bad choice but you should consider the fact that three of the sizes you tune the same way and they sound most “Uke-ish”. Therefore the baritone may not be your best first choice. You can see a good representation of these at http://www.eddyfinn.com/