Since I have not replaced every three lamps at once, I was able to compare the effect of these LED spotlights directly with halogen spotlights. The result: Both brightness and color temperature and beam angle (ie, size and shape of the "light spot") can be distinguished hardly. The perceived brightness is even slightly stronger than the 50W halogen lamps. This LED product is thus an adequate substitute.
The only downside: the efficiency is around 50 lm / W not so good for an LED light source by today's standards; There are a number of competitors who manage the better. For this, I would deduct half a star. Since you can assign only whole stars, I rounded off to four.
Another note: This LED lamps needed when you first turn a split second (estimated 0.1 to 0.2 s) until it lights up with full brightness. In practice, however, this is not a disadvantage, therefore, does not lead to a deduction of points. (Also halogen lamps do not light up "immediately".)
Overall, I do not regret the purchase. I highly recommend this product, especially since it is now getting quite cheap too; even in a "expensive" hardware store you pay no more than 10 euros.