I've been growing Mountain Princess every year since 2016 (from seeds freshly saved the previous year each year, except 2016, when I used seeds from timeless-tomatoes.com).
Anyway, this year, the fruit is about as large as it was in 2016 (when it was watered heavily, although this year it was not watered much, but it was the first time I used black plastic with it). It was somewhat smaller in 2017 and 2018, but tastier than on 2016 and 2019, too. It's later this year than any year previous. It had a sweet aftertaste/smell in 2016 that I didn't taste in other years. The fruits were softer in 2017 and 2018.