Don't have a massive amount of experience with flip fronts - I've only ever owned one! I bought it earlier this year (from
www.sportsbikeshop.co.uk), a Caberg Trip, based on the fact it fitted my head firstly and it was keenly priced (less than �100) as I only wanted it for occasional use. These two articles helped too...
http://blm.io/blog/motorcycle-helmet-safety-price/
http://www.webbikeworld.com/r2/motorcycle-helmet/caberg-trip/