Essentially, this is a pillow and a couple of strap covers. Whether or not this is useful to you depends on your requirements and the age of your little one. The pillow appears to give particular comfort to the younger baby, while the straps I think are a great idea - little ones are less fragile than we think, but they still need better protection than a lot of products give them.
The pillow is well cushioned, with two ample sized gaps for the straps of the buggy to fit through. Attaching it is not a faff at all. The same goes for the shoulder strap covers - they slide on easily enough and provide a decent amount of comfort.
What you need to consider is how much padding you want. Obviously, this is designed for a specific model, but a lot of models mirror each other and you could easily get a cheaper generic version that could cost a bit less but still do just as good a job. With our second child we didn't take any risks and went with brands, but in hindsight we could easily have saved a few pounds by getting lesser branded items, across the board really.
In terms of age range, I think this would be useful from birth to about a year old, but after that you need to look at whether it's going to be worth it. Comfort kits are often considered a waste of time and the general consensus on these is that you could use a fleece or the parts that the buggy comes with as opposed to getting this. If you're likely to be using the buggy a lot then it might be worth it as there might be a lot of motion, but if it's more for the times when you are out and about rather than expecting to be out and about all the time, then perhaps reconsider whether this is an essential or a precautionary purchase.
Features and benefits for Maclaren CosyToe Techno XT Comfort Pack - Orange Want To Know More?Comfortable head rest and shoulder pads for added comfort for your baby. Fits all Maclaren BuggysHead rest and shoulder padsOne size fits all Maclaren BuggysAdded comfort for babyDon't Forget...To check out our wide range of Maclaren products