Since this thread has been resurected I thought that I would add my thoughts...
I have both fans - the Valiant and the Caframo eco fan. I initially purchased an Eco fan, and was so impressed that I decided to buy another for my second stove, but tried the cheaper Valiant version.
So for a direct comparison (only based on one of each - so may not be true to type)...
Caframo Eco Fan - Probably the better looking fan (in my mind), neater with smaller blades. This fan definitely starts moving at lower temperatures than the Valient fan, and at any given heat appears to have a faster rotation speed. It certainly feels to move more air than the Valiant - but I am unable to quantify that. The only down side is a slight noise - not enough to annoy, but if you are close you can hear a faint 'whizz'!
Valiant - Slightly more 'clumpy' looking, with larger, curved blades (I guess there is some balance between rotation speed / blade size). It is slower to get moving, but when it does it is totally silent. It does exactly as you would expect and certainly makes a difference to the heat distribution within a room, but doesn't seem to have quite as much 'power' as the ecofan.
So in summary - both fans work and would seem to make a significant difference to the heat distribution in a room - I am very pleased with both. The more expensive Ecofan (think I paid about £90) moves more air more efficiently, however in my opinion the cheaper (£50 ish) Valiant also works well. I use the Ecofan in a large sitting / living room and if the doors are open find that it moves air throughout the room and into the hall. The Valiant is in a smaller 'snug' and evens out temperatures nicely within that room, although there is less movement into the hall (this is also a smaller stove).
Not sure if that helps at all. If you don't have a fan at all yet - then get one they are great.