Proceed with caution:

• hard railroad - the characters need to be captured (and you can't let them escape) - players hate this
• a memorable last fight in a gladiator arena with super cool mechanics - takes a lot of time to prepare and play it through mentally, be ready to fudge dice to make it interesting (and to avoid slaughtering lvl1-2 characters); the arena fight might get rather trivial if characters have exceptional mobility or teleportation spells such as misty step - best to run this for characters without these abilities
• few roleplaying opportunities
• the adventure is tweakable to fix some of the railroading issues, but requires a lot of work and soliciting ideas from the internet - one should not need to do this in a paid modue
• I would advise against running this as a novice DM