For decades GM Opel was easily the top brand in the Netherlands. Of late VW came up as an opponent and what ensued can be seen below. The first column is the year, 2nd - Opel's sales followed by position in the market and percentage of market held, 3rd - the same but for VW:
Opel's market share is down from nearly 18% to only 7% in that time and its position from 1st to 5th. VW meanwhile has increased share by three percentage points and gone top from 4th in 1990. GM has been strapped for cash at times and the product, while OK, is not class leading. VW does has good quality, if not particularly good value. I would personally pick Ford Europe as offering a better all round range than either of the above makes, but that marque only sold the same number of cars as Opel - just beating it to 4th spot.
In summary: GM Europe needs to work hard is it hopes to claw back lost ground on the sales front.