Having attended both 'events' Ole mentioned, let me try and list the Pros and Cons of both formats:

'Formal' workshop with time table:
Pros:
* You know what you are going to get.
* Pre-planning by organisers ensure classroom sessions are prepared. in the case of the F32 workshop, demonstration of hinge rule etc by projecting image of ground glass on to surfaces was an eye-opener.
* On site development gave immediate feedback.
* A well-run course ensures everyone gets attention at their own level.
Cons:
* If you aren't interested in a particular session you are left on your own.
* Have to follow the timetable, no chance to explore futher.
* Can be regimented.

Gathering:
Pros:
* Freedom to do want you want.
* 'teaching' opportunities are organic and spontaneous. Eg. A session on counting lens elements by reflections whilst consuming large amounts of whiskey and whisky.
* Location visits can extend/contract, move, evolve as required.

Cons:
* With no structure, one could get lost (Literally!)
* If you don't know anyone before hand and are not the 'soul of the party', it could be a bit lonely or overwhelming.
* You are taking a risk in going, you never know what to expect.

As Ole mentioned, his event couldn't really fail as a photographic experience, given the scenery.