I've owned both Topre 55-gram and MX Black (Filco and Leopold) keyboards. If I had to choose one, it'd be an MX Black keyboard. Topre's 55g switch is considerably heavier than their 45g switch; and I didn't care for the lack of feel in the 45g 87UB I owned. For me, the liner MX Black switch has a nicer feel than Topre's 55g, which has a barely perceptible tactile bump; and if you're a WPM is high, you won't notice the tactile bump when up to speed.
Both key switches are tiring over lengthy typing sessions; but the feel of MX Black switches have, for me, a nicer feel to when compared to Topre 55g switches. The opinions of others may differ from mine; but after owning, selling, and re-buying the keyboards, I'm going back to MX Black switches. After owning almost all the MX and 45g/55g Topre switches, I have preference for the smooth 'slide' of linear key-switches.