Learn Finnish: Meidän on arvosteltava tämä tuote ja sen suorituskyky. - We must review this product and its performance.

This is a necessity structure using the passive present participle (-tava/-tävä). When you combine a genitive subject (meidän), the verb olla (here as on), and the -tava form of a verb, it expresses that someone "has to" or "must" do something. It literally means "This product is to-be-reviewed by us." It is a common alternative to using täytyy or pitää.

How exactly do we form "arvosteltava" from the basic verb?

The basic verb is arvostella (to review or evaluate), which is a verb type 3. To form the passive present participle for this verb type, you take the infinitive, drop the final vowel, and add -tava. So, arvostella becomes arvostel- + -tava = arvosteltava.

If "tämä tuote" (this product) is the object of the sentence, why isn't it in the genitive/accusative form like "tämän tuotteen"?

This is a crucial rule for necessity sentences! When you use a necessity structure like meidän on arvosteltava (just like with minun täytyy), a total object must be in the nominative (basic) form instead of the genitive-looking accusative. That is why both tämä tuote and suorituskyky stay in their basic forms.

What are the parts of the compound word "suorituskyky"?