I'm 175cm, 80kg, average build with slightly long arms. I'm wearing a size Large, and it fits well. Great arm length, not quite figure hugging, so room for further layering in there unlikely event it's required.
I like the attached bag, sewn into the left pocket. Slightly higher side pockets good for pack strap clearance. Internal zippered pocket could be higher though (it's between chest and waist height) I would have preferred an external chest pocket.
I have Deep Space which is a very dark grey. I had expected it to be darker and maybe a little blue tint, but the site pics are not very easy to determine actual colours.
The price is high compared to a Rab or similar, but the quality definitely seems to be there. Excellent warranty. Will see how it lasts and whether I ever need to use it.
I'd give it 4.5 stars, 5 if it had external breast pocket.

What a great product for a great price compared to other jackets. Light weight yet super warm and it is flat out good looking !

I have both the hooded and unhooded versions, and have found both to be much warmer than other down jackets of similar weight. Whether it's the down being used or the construction of the baffles, these jackets don't have cold spots. And when combined with its 'stuffability', these jackets are what I wear during our Colorado winters and what I take with me on all my trips regardless of if I am going to a wet and rainy location or day spent on up Rocky Mountains.

Feature for feature, the Accelerator Down Jacket holds its own against any other 800-850 fill-power puffy on the market. One thing that stood out for me, that doesn't seem to get mentioned very often, was the quality of the zippers that Himali uses. I've seen a few companies reduce the weight of their jackets by using very flimsy zippers. The YKK zippers on the Accelerator strike a perfect balance between sturdiness and weight, and don't make me worry that I'm going to blow out a zipper in the middle of a climb. I'm 6'3, 200 lbs and can wear the XL with a midweight base layer and grid fleece beneath. The sleeves fit my 37" arms just fine with minimal riding up.

I first ordered a medium as I fit well within the size chart for that size. However I would recommend sizing up if you tend to have more muscle mass on your shoulders and chest. An exchange with customer service was very quick and very pleasant, and made the process seemless. The large in Medic Blue is a classy and mature color, but stands out well in any environment. The weight of the jacket was exactly what I was looking for as its very lightweight and very packable. The warmth is almost instant when putting it on, and the Pertex fabrics felt great even against bare skin. The hood could not feel more better fitted. A lot of other articles I have the hood is is very tight or too loose while trying to be able to fit a helmet over it. This hood cuts is perfect. It creates a seal well enough that heat is easily trapped. The attention to detail is also amazing, even on the inside of the hem of the cuff, they have imprinted the HIMALI brand. I'll be wearing this jacket on multiple hikes throughout the Whites this year. Truly an amazing jacket.