If you use the search function or browse the forums (this is the Wave section) you'll find lots of discussion about Bravo comparisons to small monohulls.
Personally I think you need to consider each boat for its own characteristics rather than performance especially when your talking about teaching children. Characteristics being setup, ease of sailing ability etc.
I use my Bravo to teach my 5 and 8 year old which I find invaluable, easy and very safe. Its not about speed but about teaching them the fundamentals of sailing.
Best of luck!
2007 Hobie 16 - 'Slingshot'
1996 Hobie 18 - 'Onrails'
Hobie Bravo - 'Hobie Bites'