This is true mostly for Estonians who live in Tallinn and either commute or work a week (or some such) in a row in Helsinki or Finland in general.
There are little befits in doing so. Tallinn is lower in cost of living sure. However doing this is a sure shot way to mess up your taxation. The Finnish tax office is fierce and they will catch anyone who does this and make sure they pay the much much higher taxes to Finland. Not paying upfront gets you heavy penalties and financial woes.
So running this setup; living in Tallinn and regularly working over in Helsinki will get you the super high Finnish taxes and other costs associated with work. Maybe there is some financial benefit in lower cost of living - however you would also have the cost of the commute and the cost of the tax bureaucracy involved. Be careful to check that those don’t cost you more than what you save in cost of living.
Quality is hard to assess: depends on what you are after. Helsinki is a bigger city, sure, Tallinn however has many good qualities too.