The Marmot Reactor fleece doesn't fall shy of Marmot's high reputation for gear. The jacket is very comfortable and fits pretty true to size. As someone has already pointed out in a previous review, if you're purchasing the reactor as a solo outerwear piece and expecting to stay warm in freezing temperatures, look elsewhere. However, the reactor serves as a nice and very functional midlayer, even with the lower fleece weight of 100. I also own a Marmot Tamarack outer shell jacket that can house the reactor as a zip-in. With a moisture-wicking baselayer beneath, this is a great combination, as I use it for backpacking and hiking. If you're interested in a heavier zip-in midlayer for a Marmot jacket, you might also check out the Marmot Warmlight fleece (similar to the Reactor but with heavier 200 weight fleece)but as long as you're purchasing the Reactor fleece with reasonable and appropriate climate expectations, you can't go wrong with this one!

Bought for my husband. He loves it. Perfect fit!!

I bought the vest at first in the reactor series .... i loved it, decided i wanted the same light option, but with sleeves for early spring and late fall ... Wind does rip right thro it, but as under a wind shirt or rain/wind shell .... its a perfect light fleece option, pockets and an inner pocket for ipod/mp3 ... I'd buy it again and trust marmot's quality ... I own several pair's of their clothing and never returned an item.

When It says light fleece,its light bloody fleece.Very light weight good for layering,but not good on A chilly day by its self.Good for exercise training or walking your dog in the afternoon.

I purchased the Reactor fleece about a month ago and since then, it's packed with me whenever I head out. It seems to have a great weight-to-warmth ratio which I wasn't expecting. While this fleece is great as a mid-layer, you can definitely use it everyday even when temperatures get below freezing.

This is a good fleece jacket. I use it when i go out skiing or snowboarding. Not the best jacket for alone use, but its still a solid buy.

I don't see what all the fuss is about... Others who have reviewed this piece negatively seem to have expected the wrong thing from it. This is an excellent LAYERING piece. No, it doesn't cut wind or keep you warm as an outer layer; that's not what it's supposed to do. I bought mine a bit small, and the tighter fit works excellent for layering underneath my down jacket or softshell. Get it on sale, and you won't find a better layering piece for the price.

It is light and works perfect as a second or outer layer for my winter trail running or snowshoeing. Maybe as a light fall or spring jacket but it is too light to be a primary in any real cold weather. It does what I bought it for. Price is reasonable when on sale and has Marmot quality.

echoing previous reviews - good midlayer, not good stand alone. purchase for added insulation. took it on a month long mountaineering trip and it served me well on travel days where it was too cold for just a shirt, but not quite at a level for a insulated puffy jacket. if the wind hits big time, or if you sit down for a rest, throw on a wind layer. you'll need it

This is an okay fleece for a liner, but it's paper thin and the wind would rip right through it. I returned it...so that's all I got

really light fleece, acts accordingly for wind - doesn't have any stopping power, but that's not why you're buying this fleece.

good for a layer over a base when it's not cold enough for a 300 weight, but too chilly for just a t-shirt.

haven't taken it out on any trips yet, but will. feels like the fleece around the zipper part at the bottom is wearing thin already. THREE STARS!

incred warm for such a wee light fleece. stretches just enough. deep pocks. great hideaway pock. don't leave home without it!! j r

First of all, girls love hugging you when you wear this soft and fuzzy jacket :)
This jacket works great on cool mornings by itself, or as a very effective mid-layer under a windproof shell.
Great fit, too.

Marmot may have the very softest fleece out there. This is a lightweight, comfortable jacket & super soft. Cut a little fuller than some of there other jackets, as I am 5'10", 160 lbs and usually like to wear a large, but I am right in between a medium & large in this jacket. Looking for a firly basic lightweight fleece jacket - can't go wrong here!

It fits great, it's light and warm; It does what is supposed to and it looks good.

It is a good fleece for morning workouts. It wicks well and keeps the chill off. The jacket is light fleece, so you get what is advertised. I have a 40 chest and the large was a little big, but I can still layer it without a problem. I would say it is true to size since the chart states I should have bought a medium.

Great fleece, its lite weight and zips into my North Face shell. Also, this fleece appears to be high quality made.

It looks like it was purchased at Kmart. It's not worth the sale price. I sent it back.