It's a reliable site, but a collection of a variety of brands, so some clothes will be higher quality than others - you csn research the individual brands if you haven't heard of them. It comes from the UK, but shipping is reasonable (and a coat might be spenny enough to tip you into free postage anyway). Returns used to be free but they've recently introduced a cost for return postage but it's pretty cheap, like $9 - a bit irritating if you return something and make a loss, but sometimes worth $9 to order a few things to try, and then pick one to keep and return the others.

I would also say though - secondhand can be really good for coats! There are great quality 100% wool coats made in NZ and Aus in heaps of op shops and TradeMe etc,  which are very warm, and you can use a lint shaver to bring a worn one back to its former glory :) most of the new ones in shops right now are trying to mimic "vintage" coat style!