Based on my experience, the hard product (i.e. seats) of VS beats AY by far (full flat fishbone vs. angled 2-2-2). But AY is still more spacious than AA. In terms of food, AY beats VS and very clearly AA.

However, the transit in HEL beats the transit in LHR by far, very easy and without hassle.

So in my view, the bottom line of AY and VS almost the same. For me, this is one of the cases I would go by the fare. But both are superior to AA.