We have been working with the frog system on our site for nearly 3 years now. I agree with the other people who have highlighted its positive points but a couple of additional things need to be stated.
I understand why it is so enthusiastically supported by especially by so many teachers and other users, even though those on the technical side can get a bit sniffy about it, it is a great bit of kit for the user. I have looked at other systems before and after we bought into frog but none have tempted us ....as yet.
Over the years we have always felt that the support that frog provide has been good but the thing we like best is the way this company actually listens and responds to teacher needs and builds them into the system.
I was amused by the frog screenshot and the comments about it. The fact is that the 'front end' of frog is whatever you want it to be. In fact it is so easy to set up 'areas' that teachers and pupils can easily design and run different sections in pretty much any style and with whatever content they choose.
From the technicians point of view it is pretty easy to manage as well ... a couple of days and you have it all sorted out. Obviously designing pages etc takes time but it is not difficult and with only a little planning training much of the designing and implementation side can be done by teachers (or pupils if you wish).
The frog teacher side is heavily used by our staff to such a extent that it has become 'mission critical' in so far as they tell me that they could not function effectively without it now!
In my own LEA a number of schools have bought into frog (even though the LEA wide solution is provided at no local cost ) and it is in frog schools that the teachers and pupils are becoming engaged with the 'VLE process' to support teaching and learning.
I am sure that there are other good solutions out there which suit different schools and frog does have its quirks dont get me wrong, but in terms of bang for your buck it is one of the best purchases we have made.