Kevin Lwrote a review of Karhu Footwear Flow 3 Trainer Fulcrum Running Shoe - Men's on June 10, 2014
Familiarity: I've used it once or twice and have initial impressions
Fit: Runs large
Size: These seem to run a little large. I normally wear 9.5 with Nike frees and 9.5 New Balance Minimus shoes which are "true to size" and ordered a 9.5. I exchanged these and will have size 9 coming. I would compare Karhu sizing to be similar to Adidas shoes as they to run about half a size larger.
Weight: These shoes are extremely light weight. When held to the light, the light can shine through. The mesh is very breathable yet still has enough structure to keep it's shape.
Technology: The fulcrum helps but my perception of padded running shoes may be skewed. I am not used to running shoes without any sort of drop as I have been wearing minimal shoes to practice my gait. Now that I have developed a mid strike I decided to get some shoes with padding as it will help on longer runs. The drop helps keep me moving forward which may or may not be attributable to the fulcrum technology.
Overall: I recommend these shoes to anyone serious about running, my only gripe is that these are rarely on sale but you will get a quality shoe. Just be aware the size may be a half size larger than you are used to. No regrets buying this shoe.