Vlad V.
Yelp
I have had the pleasure of exploring Rome pretty extensively and Trastevere is hands-down my favorite part of town. I've spent two evenings here and I have stopped by during the day too. People describe this neighborhood as the Greenwich Village of Rome. What you'll find is a lively part of town, especially when the sun sets.
First off, there are a ton of good restaurants in the area. Including some highly rated, popular restaurants where you'll see lines as well as casual pizzerias. And everything in between. Two of my favorites are Dar Poeta (pizza) and Trappizino (if you know, you know).
Trastevere is also known for its nightlife. There are a ton of bars to choose from and a lot of them offer happy hour (aperitivo deals). You have bars that have been listed on lists of the world's top bars so like the dining scene, the drinking scene is done at a high level.
In addition to the places you can go, it's the vibes that deliver too. You'll see street performers. Singers that draw crowds. And other entertainment. The best way to enjoy the experience is to walk around, enjoy the sights, and pop in wherever your heart desires. Next thing you know, you've spent hours in Trastevere. It's not only my favorite neighborhood in Rome but also one of my favorite neighborhoods period.