The Gaggia Classic and the Gaggia Classic Pro are very similar machines. The main difference between the two is that the Pro model has a few additional features, such as a cup warmer and a higher-quality portafilter. The Pro also has a slightly higher price tag, so it's up to you whether or not these extra features are worth the additional cost.
The Gaggia Classic is an excellent choice for those who want an easy-to-use machine that produces delicious espresso without any hassle. If you don't mind spending some time learning how to use a semi-automatic machine, this is definitely the model for you. And if you're willing to spend a bit extra for the Pro model, you'll get even more features and convenience. Either way, you can't go wrong with the Gaggia Classic.