Presumably very good.
Captured at Portinhoikka on 1944-06-25, after which its gun was removed, and it was used by the Finnish army as a towing vehicle until 1964. The gun was added back on when it became a museum vehicle.
https://www.panssarimuseo.fi/wp-content/uploads/2017/11/Raskas-rynn%C3%A4kk%C3%B6tykki-ISU-152_esittelytaulu.jpg
From museum website