Living it.
Pros - better work-life balance; more responsibility; less 'politics'; greater satisfaction
Cons - requires more commitment; do more admin; little support services (do everything); make less money (generally); probably lose big company clients
The issue is really where you are in your career. If you are still "building" a career you wont get as much development in small firm but you get a lot more challenge. If you are mature consultant (whatever that means)it can be a good life. Hope this helps.