Lisa, the clothes are not designed for tall, willowy women. Like many companies, that is the type of model they use, but it is far from representing the main customers. Our customers often also wear Eileen Fisher, and the two looks mix pretty well together. My take is that OSKA presents a more distinctive style and skews more casual overall than Eileen Fisher. I would say our customers at the Seattle store run the gamut of shapes and sizes within a misses range that is generously proportioned. Our size 0, or extra small, is like a US 4 or 6, so there isn't much available for women who would take the smallest sizes in other brands. The designers of the OSKA line and its sister ISCHIKO are both women, and I think they do a good job of designing for women's bodies. Almost all OSKA pants have elastic in the waist, most often just in the back, while also having a fly front. (ISCHIKO has a slightly younger feel, and the pants generally don't have the elastic waist, unless they are a track-style.) The fabrics and construction are mostly European.
In the US, OSKA doesn't pay for return shipping, so it's hard to try things and return them. I don't know what the policy is in Canada (the company doesn't ship internationally). So it would be best if you could find a local boutique that carries some OSKA pieces to try in person.