"In cases when" vs. "in cases where"

Since you use "in cases..." I'd say where, because you specified a "location" when you said "is more suitable in cases where..."

You could instead use when if you deleted that part so:

...is more suitable when users' needs...

Go with 'where' because, as @Alenanno states, you have said 'in cases' which hints at a location, though an abstract one.

You could use 'when' with a slight reword: '...suitable at times when...'.

@Mickeyf 's suggestion (in which) would normally be a good substitute but in this particular case it would leave you with a repetition of 'in', which sounds clumsy. This option would fit better if you went with '...suitable for cases in which...'.

So, I would say that those are your choices.

Hope that helps.