Absolutely worth it. I bought it twice (once for N4, again for N3). The AI tutor alone is gold — it adapts to YOUR pace, not some arbitrary schedule.
Here's my take: if you're methodical (which sounds like you), the Deep Dive study plans are perfect. They don't rush you. You can stretch a 30-day plan into 90 days and it still works.
The system prompt on page 52 changed how I use ChatGPT for practice. Worth the $7 just for that.
If you're on N5, start with the free tier. If you're N4+, buy it.