I have three Madewell items: a secondhand Fleet Jacket in dark grey, a little bandana in an elusive shade of sage/faded olive (purchased w/ store credit), and a pair of Langford wide leg crops in a russet color (new, deeply discounted at Nordstrom, haven't cut tags yet). I've been curious about the Courier shirts, but *really* do not need any more tops this year. The pants fit great, but I've returned a bunch of jeans that I thought I would love and didn't. The jacket is really nice, almost perfect, I just wish it had a little extra room in the shoulders. So, I think some of their fits are too straight/rectangular for me, but not to the same degree that J Crew has been lately. And I think Madewell's sizing and quality are more consistent.
Like Viva says, they have a very West Coast vibe. I grew up in New England and I didn't understand the Madewell look until I'd lived in southern Nevada for a while. Those oversized cotton shirts stopped looking ridiculous and started looking... comfortable. I'm not surprised that Madewell works so well for Texstyle! (Ironically, the original Madewell was a brand with deep New England roots...)
The colors tend to be a little muted and washed out for me -- I prefer to take one piece and mix it with stronger colors from my existing wardrobe. The grey jacket, for instance, looks great with deep red or burgundy underneath. And if I keep the russet pants, I'll probably wear them most often with navy/white or black/white tops.
Also, if you don't have a Madewell close to you, sign up for "Madewell Insiders" on the website -- it gives you free return shipping and a $25 gift card on your birthday.
