I bought this based partly on Fiskars reputation but principally on the extension length (a massive 4m) my thoughts were that it would probably be unusable at that length but maybe ok at about 3m. To my surprise it worked perfectly at full extension very easy to cut up to 3mm branches even at full stretch. The biggest problem was getting the cut angle right at full height, you need to keep adjusting the head angle so you can see the blades properly.
Although very light you do need to be fairly strong to use this for any length of time as your arms quite quickly begin to ache.
All in all an excellent product, very well made and easy to use.