Definitely recommend Prison Breakers for first timers.
In terms of space, the rooms are relatively small. In other words, you may feel a bit cramped when escaping these rooms with a larger group. Similar to Esc-It, you will be introduced to a story to get your mindset behind the theme of the room.
The room we escaped was Cold Case. On the website, they mention that this room 'can be a scary and stressful experience for some players.' The room is almost pitch black, but Don't worry, NOTHING pops out at you to intentionally scare you (I don't know about your friends though ;) .
We actually really enjoyed Cold Case, the puzzles made sense and weren't just a series of math problems like other places included. Compared to Esc-It, the Cold Case room is definitely a bit more thematic. They have another room called Poker Face which is more difficult than Cold Case, but we have yet to plan a date to escape this room.
Great customer service too - the owners are very accommodating and extremely nice!